This Nanaimo Bar Cake takes the classic Canadian treat and transforms it into a delicious layer cake! Chocolate cake layers with a vanilla custard frosting and chocolate coconut crumble.
There’s a good chance you are probably reading this right now and thinking – what the heck is a Nanaimo bar?!
Rest assured, you are not alone. Unless you grew up in Canada or have a passionate Canadian in your life, you likely won’t have heard of this amazingly delicious treat. Those who do know it though, know that it is ubiquitous around here. You’ll be able to find Nanaimo bars in every grocery store and every local bakery across the country.
What is a Nanaimo Bar?
A Nanaimo bar is a no bake treat made of a chocolate graham cracker/coconut base (sometimes also with almonds), followed by a yellow custard filling and finally a layer of chocolate. According to Wikipedia, there seems to be a bit of controversy as to where the bar actually originated, but to avoid any potential wrath, I’m going to stick with saying it was in Nanaimo, BC.
Did you KNOW (and this is news to me) that you can do a self-guided tour in Nanaimo and try over 30 different variations of Nanaimo bars?? They have a map with all the delicious locations you can hit up. Amazing. That Nanaimo bar milkshake is calling my name.
Nanaimo bars are known for their signature yellow custard layer. There is really nothing like it. There’s also not much to it, to be honest. It’s basically butter, powdered sugar, and custard powder (which is what gives it that signature yellow color). I’ll fully admit that the only things I’ve ever used custard powder for are this cake and actual Nanaimo bars. I wish it came in a smaller container! It’s not a bank-breaker, but I don’t like to see things go to waste.
What can be used instead of custard powder?
I’m not sure how readily available custard powder is outside of Canada and the UK, but it doesn’t seem too hard to find, as both Amazon and Walmart seem to carry it. The main ingredient in custard powder is cornstarch, so you can try to replace it with that and increase the amount of vanilla for taste. You won’t be able to get that signature yellow color this way, but it would still be delicious.
Ideally though, use the custard powder if you can find it!
When making this Nanaimo Bar Cake, I ran through a few different options. My first plan was to incorporate the graham cracker crumbs and coconut right into the cake batter, but I nixed that for two reasons:
- This chocolate cake batter is very thin, so I imagined the coconut would just sink to the bottom.
- The graham cracker and coconut flavor would likely be lost in the rich chocolate cake.
Instead, I decided to do a crumble layer to make sure the flavor of that classic Nanaimo bar base came through, but also to add some texture.
I wanted the decoration of the cake to emulate a Nanaimo bar as much as possible, so I kept it simple — a naked cake so that you would see the layers of chocolate and custard, and a drippy chocolate ganache to evoke that top layer of the Nanaimo bar. If you wanted to, you could put some ganache between the layers too. I think that would be a nice addition, but I would double the ganache recipe if you plan to do that.
If you love Nanaimo bars as much as I do, you will love this Nanaimo bar cake! It’s basically a deconstructed Nanaimo bar with rich chocolate cake layers. What’s not to love?? For my non-Canadian friends, I really hope you will give this one a try. It is totally delicious, and you’ll wonder why Nanaimo bars haven’t infiltrated every part of the world yet.
Looking for more Chocolate Cake recipes?
- Peanut Butter Chocolate Cake
- French Silk Pie Cake (Copycat Deep n’ Delicious Chocolate Cake)
- Chocolate Strawberry Cake
- Mocha Chocolate Cake
Tips for making this Nanaimo Bar Cake
- The cake batter is very thin and rises a lot. Do not be alarmed by this!
- If you can’t find custard powder you can try to replace it with cornstarch and increase the amount of vanilla for flavor.
- For the crumble layer, use fine shredded coconut if you can find it, but it’s not critical.
- If you like, you can sprinkle more shredded coconut over the crumble layer when stacking the cake.
- For the ganache, I find that a good quality chocolate makes a huge difference. I use Callebaut because that’s what is available to me.
- To help ensure your cake layers bake up nice and flat, check out my Flat Top Cakes post!
Nanaimo Bar Cake
Ingredients
Dark Chocolate Ganache:
- 3 oz good quality dark chocolate
- 3 oz heavy cream
Chocolate Cake:
- 1 1/2 cup all-purpose flour
- 1 1/2 cups granulated sugar
- 3/4 cup Dutch-processed cocoa powder sifted
- 1 1/2 tsp baking soda
- 1 tsp baking powder
- 1 tsp salt
- 1/4 cup vegetable oil
- 3/4 cup buttermilk room temperature
- 3/4 cup hot water
- 2 large eggs room temperature
- 2 tsp vanilla extract
Chocolate Coconut Crumble:
- 3/4 cup graham cracker crumbs
- 1/4 cup fine shredded coconut unsweetened
- 2 Tbsp granulated sugar
- 1 Tbsp Dutch-processed cocoa powder
- 1 tsp black cocoa powder optional (for color)
- 1/4 cup unsalted butter melted
Vanilla Custard Frosting:
- 1 1/2 cups unsalted butter room temperature
- 4 cups powdered sugar sifted
- 1/4 cup custard powder
- 2 Tbsp heavy cream more if needed
- 1 tsp vanilla extract
Instructions
Dark Chocolate Ganache:
- Finely chop chocolate and place into a bowl. Bring cream just barely to a simmer and pour over chopped chocolate. Cover with plastic wrap and let stand 2 mins. Stir with a spatula until combined, smooth, and silky. Set aside to cool completely until thickened but still pourable. See notes.*
Chocolate Cake:
- Preheat oven to 350F, grease three 6″ round baking pans and dust with cocoa powder. Line bottoms with parchment.
- Place all dry ingredients into the bowl of a stand mixer fitted with a paddle attachment. Stir to combine.
- In a medium bowl whisk all wet ingredients (pour water in slowly as not to cook the eggs if very hot).
- Add wet ingredients to dry and mix on medium for 2-3 mins. Batter will be very thin.
- Pour evenly into prepared pans. I used a kitchen scale to ensure the batter is evenly distributed. Bake until a cake tester comes out mostly clean. A total of 35-40mins.
- Cool 10 minutes in the pans then turn out onto a wire rack to cool completely.
Chocolate Coconut Crumble:
- Preheat oven to 350F and line a baking sheet with parchment. Whisk all dry ingredients in a medium bowl. Pour in melted butter and stir until it begins to clump.
- Spread evenly on baking sheet and bake for 15mins. Cool completely before using on cake.**
Vanilla Custard Frosting:
- Prepare a stand mixer with a whisk attachment. Whisk butter until creamy, scraping bowl as needed.
- Reduce speed to low and add in powdered sugar 1 cup at a time until well blended, add custard powder. Increase speed to med and beat for 3 minutes.
- Add vanilla and 2 Tbsp cream and continue to whip on medium for 1 minute.
- Add more cream as needed until desired consistency is reached (I added all 4 Tbsp). Whip until the frosting is smooth and silky.
Assembly:
- Place one layer of cake on a cake stand or serving dish. Top with about 2/3 cup buttercream, spread evenly. Sprinkle some of the crumble on top. Repeat with remaining layers, but don’t sprinkle crumble on the very top layer.
- Frost and smooth the outside with a thin crumb coat (thicker on the very top). Chill for 20mins.
- Using a small spoon, place dollops of ganache around the top edges of the cooled cake, allowing some to drip down. Fill in the top of the cake with more ganache and spread evenly with an offset spatula.***
- Use a 1M tip to pipe dollops on top with remaining frosting and sprinkle some crumble in the middle.
Notes
** You will have some crumble leftover after using it in the cake. You can use this as a topping for ice cream or a crunch layer in another cake.
*** You may have some ganache left over.
Barb says
I plan to make this cake for my son’s birthday, so I haven’t made the recipe yet yet. However I was wondering if coconut could be replaced with maybe rolled oats? Our family has some fussy eaters and a nut allergy to avoid and coconut falls into the dislike category. I thought perhaps running the rolled oats through a food processor to chop them up might work? I was wondering what your thoughts might be.
Olivia says
Hi Barb! I would give that a go. It will change the flavour and not be traditional Nanaimo bar but it should still taste delicious 🙂
Kim says
Fantastic recipe. Perfect adaptation of Nanaimo Bar into cake. For extra creamy frosting I add 2 Tbl whole milk powder. Also did a thin coat of frosting on the bottom of layers 2 and 3 to help it stick to the crumbles. I’ll passn this recipe for sure.
Olivia says
Thanks so much, Kim! I’m glad you loved it 🙂
J. Dewhurst says
Hi,
How do you store thsi cake?
Olivia says
Hi J! It will be fine at room temperature for a few days but I tend to store my cakes in the fridge and then take out 2-3 hours before serving.
Isobel says
I added espresso powder with the hot water and I also toasted coconut and added it along with the crumble.
Olivia says
Glad you liked it, Isobel!
Cynthia says
Is there a reason that you use buttermilk in the chocolate cake? I’m a supertaster, so I don’t care for anything acidic in my cakes. Do you think regular milk would work as well as the buttermilk?
Olivia says
Hi Cynthia! The buttermilk is needed for this recipe as there is a lot of raising agent and it needs the acid to properly rise. I have never found the cake to be acidic.
Krista says
Can’t wait to try this! Could it be made as is in 8 or 9” cake pans?
Olivia says
Hi Krista! For sure, you’ll need to scale the recipe up though. Here are some sites I use as a guideline:
http://www.joyofbaking.com/PanSizes.html
https://www.cookipedia.co.uk/recipes_wiki/Cake_tin_conversion_charts
L Stevens says
Excellent yummy recipe, tastes just like nainamo bars.
I also wanted to add that vanilla instant pudding mix can also be substituted for custard powder. I’ve made nainamo bars for year (in the U.S.) and usually can’t find custard powder. With the pudding mix, you wouldn’t have to worry about adding vanilla.
Olivia says
Hi L Stevens! So glad you loved it. Thank you for the tip!
Tessa says
I’m in the process of baking this cake now, and the coconut crumble burnt completely. 15 minutes seems way too long at 350? Is there a mistake with those instructions? I took it out at 13mins and it’s completely black.
Olivia says
Hi Tessa! It should not have burnt at 15mins. It will be black due to the black cocoa powder.
Tessa says
I never put any black cocoa powder in! That’s not something I could find where I live. It definitely burnt. I opened the door to the oven at 13mins because I could smell burning and smoke was wafting out. I triple checked the recipe and did everything exactly as written for the crumble aside from the black cocoa. I remade the crumble and cooked it for only 8 minutes and it was perfect.
Olivia says
Oh, strange! Maybe your oven gets hotter than mine. Every oven bakes a bit differently. Glad you were able to fix it 🙂
Julia says
The same thing happened to me. I cooked it on the parchment paper on a dark pan and so I tried it again on parchment paper on a light aluminum pan and it cooked perfectly. Hope this helps!
Christina says
Could I use 3/4 cup hot coffee instead of hot water for the cake?
Olivia says
Hi Christina! Yes, that will work totally fine.
Chondra says
Vanilla instant pudding mix can used in place of custard powder. Instant pudding mix is readily available in the US.
Olivia says
Hi Chondra! You can use pudding but it won’t have the exact flavour as the custard powder.
Russell says
How come you didn’t use German custard buttercream? Do they taste the same?
Olivia says
Hi Russell! No, they taste quite different. Custard powder is traditional in Nanaimo bars.
Russell says
Thanks for that. I can’t wait to try Your recipe. It looks amazing
Jess says
This looks amazing! I’d like to try my hand at baking this for my boyfriend’s birthday, and just wondering if regular cocoa powder would work in the recipe? (we have A LOT of it at home!) Thank you so much!
Olivia says
Hi Jess! Regular should work just fine. Let me know how you both like it!
Julia says
Delicious! I added about 1.5x custard powder to the icing cause I found it didn’t taste enough like custard. I also made this totally dairy free – anything that called for butter I did half vegan butter and half vegan margarine (to find a happy medium between texture and taste), and anything calling for heavy cream I used a can of coconut milk (I refrigerated it and used the thick creamy part). Delicious, everyone at my party loved it! Even the non-dairy free people!
Olivia says
Hi Julia! So glad everyone loved it. Thanks for your vegan tips!
Ashley says
Most delicious cake ever! Loved everything about it! Thank you
The chocolate cake was a first for me making from scratch and I loved it. I am planning on using the recipe for my sons birthday cake…how long would you recommend baking it in a 13x9x2 pan?
Olivia says
Hi Ashley! So happy you loved it. Baking time is hard to say as there are so many factors. It should be similar though, but be sure to check on the cake as it’s baking. Here are the steps I run through when I’m testing if a cake is done:
1. Peek through the oven window. To see if the cakes are a nice golden brown (doesn’t really work for chocolate cakes).
2. Nudge the oven. Gently nudge your oven (assuming it’s free-standing and not built-in). If there is any jiggle in the center of the cakes, leave the oven door closed and bake for a few minutes longer.
3. Nudge the pans. Open the oven and gently nudge the pans. If there is any jiggle in the center of the cakes, close the oven door and bake for a few minutes longer.
4. Poke the cake. Gently poke the top of the cake with your finger. If the cake is firm and springs back, it’s ready for the next step.
5. Toothpick test. Insert a toothpick into the middle of the cake. When there are a few crumbs on the toothpick, the cake is ready. You want crumbs on there because the cake keeps cooking when you take it out of the oven.