This post contains affiliate links. Read the full disclosure here.
This is the easiest, no-fuss vegan sheet cake EVER. Assembled in the same pan you bake it in, this cake has no eggs, no butter, and no milk, so you're pretty much guaranteed to already have all the ingredients on-hand. It's moist, fluffy, and topped with a fudgy chocolate wacky cake frosting for extra chocolatey-ness.
Growing up, this was literally the only cake my mom ever made up. I mean I truly don't remember her ever making any other cake recipe, and I was perfectly content with that because this cake is seriously all you need.
When I was a kid, my mom rarely put any frosting on this cake. It's that delicious. However, frosting on a cake is never going to NOT be delicious so now a-days I like to level it up a bit with a fudgy chocolate buttercream.
Why is it called Wacky Cake?
This cake is naturally vegan, but it was created before that term even existed (Fun fact: the word vegan was coined in 1944. The more you know!). It's wacky because it is made with no eggs, no milk, and no butter, but is still incredibly moist and fluffy, so you could never tell that it's missing those ingredients!
My mom made a few adaptations to the recipe she was given 30 years ago, and I made a couple more tweaks to it, but until recently I had no idea about the origins of Wacky Cake.
It turns out, Wacky Cake is also known as Depression Cake because it was created during The Great Depression, when certain ingredients were scarce. Such an odd name for a delicious chocolate cake that brings so much happiness, so I'm going to just stick with calling it Wacky Cake.
STEP BY STEP INSTRUCTIONS
This is a one bowl vegan chocolate cake, so all the ingredients are mixed right in the cake pan you bake it in. That means less dishes (a baker's dream), and it comes together in under 10 minutes.
This recipe is for an 8x8 square baking pan but if you are making it for a larger group it's really easy to double it and bake in a 9x13 (baking time is roughly the same).
STEP ONE: First, mix all dry ingredients in the baking pan until any clumps are gone, making sure to scoop around the edges and corners of the pan to mix everything well.
STEP TWO: Make 3 wells in the dry mixture and distribute the oil and vinegar between them. Finally, pour the water over the entire mixture and mix with a fork until fully combined, once again making sure to get right into the corners.
STEP THREE: Bake the cake and check it every minute after the 22 minute mark. A toothpick inserted in the middle should come out clean but if you over-bake it you'll end up with dry cake!
Fudgy Chocolate Buttercream
Topping this vegan sheet cake with extra fudgy vegan chocolate buttercream makes it a chocolate lovers DREAM. Yes, buttercream can be dairy-free and still taste exactly like the real deal!
Now, vegan butters on their own don't easily hold their shape at room temperature, so this buttercream uses a mix of butter and vegetable shortening. I use a 2:1 butter to shortening ratio so that you don't get that shortening taste.
This buttercream uses a full ½ cup of cocoa, which is what makes it extra chocolatey (I'm not complaining). If you're looking to go the less chocolatey route, this cake also pairs really well with whipped cream or vanilla buttercream.
FAQs and Expert Tips
Can I use regular butter for the buttercream?
Yes! You can substitute regular butter and regular milk in the buttercream.
Can I use another flavour of frosting?
Absolutely! This cake goes well with chocolate orange buttercream, coconut buttercream, vanilla buttercream, or even without frosting! You can dress it up however you'd like!
- Make sure to not over-bake the cake! I always recommend starting at the lower end of the bake time, then check the cake with a toothpick inserted in the middle every 1 minute after. The cake is done when the toothpick comes out clean but over-baking will lead to a dry cake!
- Make sure to really scrape around the corners of the pan, as sometimes dry ingredients can get stuck in there.
- Try to get out any clumps in the dry ingredients before adding the wet to make sure all ingredients combine evenly.
Storage & Doubling Instructions
How do I store this cake?
This wacky cake, like most chocolate cakes, is best enjoyed at room temperature, and the buttercream holds its shape and texture extremely well. Store it in an airtight container or tightly covered for up to 4 days.
Can I freeze the buttercream?
The perfect buttercream to cake ratio is a very personal thing, and some people like to lay it on super thick! This recipe makes enough buttercream for a thick layer of frosting on the cake, but if you prefer a thin layer, you can halve the buttercream recipe or freeze the leftovers.
What I love about this buttercream is that it freezes perfectly. I have probably 5 containers of leftover buttercream in my freezer at any given time.
Freeze any leftover buttercream in an airtight container for up to 2 months and remove it from the freezer a few hours before you want to use it. Then, just give it a quick stir, and you've got smooth, fudgy, I-just-whipped-this-up buttercream.
To double the recipe and use a 9x13 pan, simply double all the ingredients and bake for around 25-35 minutes, or until a toothpick inserted in the middle comes out clean. You can also double the recipe using two 9 inch round cake pans.
More Recipes You'll Love:
- Pretzel Brookies Cookies
- Stuffed Cookies and Cream Cookies
- Strawberry Banana Chocolate Chunk Muffins
PIN IT FOR LATER!
If you make this recipe, let me know how it went in the comments, I’d love to hear from you! You can also tag me on Instagram or Facebook so I can check it out!
Wacky Chocolate Cake
Wacky Chocolate Cake
- 1⅓ cup +1 tbsp all-purpose flour
- ¾ cup granulated sugar
- ¼ cup cocoa powder
- ¾ teaspoon salt
- 1 teaspoon baking soda
- 1 teaspoon baking powder
- 1 tablespoon white vinegar
- ⅓ cup canola oil (or other neutral oil)
- 1 cup hot water
Wacky Cake Frosting (Fudgy Buttercream)
- ½ cup butter (vegan or regular)
- ¼ cup vegetable shortening
- ½ cup cocoa powder
- 1¾ cup powdered sugar
- ½ teaspoon vanilla extract
- 1-1½ tablespoon milk of choice (if needed)
Wacky Chocolate Cake
- Preheat oven to 350F.
- With a fork or spoon, make 3 wells in the dry mixture and evenly distribute the oil and vinegar between the them.
- Pour the water over the entire mixture and mix with a fork until fully combined, making sure to scoop the corners to get any remaining dry ingredients.
- Bake for 22-26 minutes or until a toothpick inserted in the middle of the cake comes out clean. Do not over-bake! After 22 minutes, check the cake every 1 minute. If you over-bake, the cake will be dry!
- Allow the cake to cool completely before frosting.
Wacky Cake Frosting (Fudgy Buttercream)
- With a standing or electric mixer, whip together the butter and shortening until smooth.
- Mix in the powdered sugar, then the cocoa powder until well combined.
- Add in the vanilla, followed by the milk. If the buttercream appears too thick, mix milk in a ½ tablespoon at a time until it reaches the desired consistency. If it’s still too thick, add another ½ tablespoon of milk.
- Once the cake has cooled completely, spread the icing on the cake using a spatula.
- It’s ready to eat! Slice smaller pieces if desired. Store leftovers in an airtight container on the counter or in the fridge.
This post contains affiliate links. As an Amazon affiliate, I earn a small commission from qualifying purchases, at no cost to you.
Hi, when you hit the metric tab the oil and water still stay in cups and all the buttercream ingredients are in cups. Please could it be changed. Thank you
My cake turned out very nicely, although I had one minor flaw. In the instructions it told me to mix everything together in an 8x8 cooking pan, and I did as it said, although, it says to put in an u͟n͟g͟r͟e͟a͟s͟e͟d͟ cooking pan. I did exactly that, but when I tried to get the cake out of the pan, it was stuck and didn't come out even when it was fully cooled down. Otherwise, the cake and frosting was amazing, and this is probably one of my future go-to recipies! ?
Hi Andy! Thank you for the mentioning the part about the ungreased pan, I will add a note in the recipe about that! But I am so happy to hear that you loved the recipe, thanks so much for the review!!:)
I'm 53 years old and my grandmother always told me stories on the depression. I grew up on Wacky Cake! Her old recipes are always showing up online and this is one of my favorites! Thanks for the blast from the past!
Hi Cheri! So glad to hear that this brought back memories - it's one of my favorite cakes ever too 🙂 Thanks for stopping by!
What can I use instead of white vinegar, would apple cider vinegar work as well?
Hi Megan, I think apple cider vinegar would work fine!
Made this cake and frosting to try with my son who will turn one at the end of the month and can’t have dairy. He loved it. I used vegan butter and chocolate almond milk in the frosting. It was delicious. Do you know if I kept the recipe size the same, could I make 2 six inch cakes?
Hi Allison! I'm so happy you both loved the recipe and chocolate almond milk sounds delicious! To make 2 x 6 inch cakes you would keep the recipe the same, yes. I'd start checking on the cakes about 5 minutes earlier and the baking time could be different. You may have to make more buttercream (around 1.5 times more) depending how much you'd like to decorate and pipe the cake, but you can always freeze the leftover frosting. Enjoy and happy early birthday to your little one! 🙂
Hello! The cold water in the receipe is actually chilled water from fridge or room temperature water is okay?
Hi Monika! If you have water chilled from the fridge then you can use that, but if you don't, then room temperature will be fine. Thanks for stopping by 🙂
Very moist, super light and delicious, just wondering if you have tried with coconut sugar!
Hi Fernando! I'm so glad to hear that you liked the recipe! I haven't tried making this cake with coconut sugar myself, but I think it would be fine to substitute at a 1:1 ratio with the granulated sugar 🙂 Thanks so much for stopping by to leave a review!
I made this three weeks in a row - SO easy and always turns out fantastic!! This is my new go to chocolate cake for sure.
Hi Ellen! I'm so happy to hear that you love the recipe and find it easy to follow! Thank you so much for taking the time to leave a review 🙂