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5 from 10 reviews

This is the easiest, no-fuss chocolate snack 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.

a piece of vegan sheet cake with wacky cake frosting

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.

a vegan sheet cake with sprinkles and wacky cake frosting

Why is it called Wacky Cake?

This cake is naturally vegan, but it was created before that term even existed. 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.

a piece of vegan sheet cake with wacky cake frosting

Step By Step Instructions

Note: Full ingredient measurements and instructions can be found in the recipe card at the bottom of this page.

This is a one bowl vegan chocolate snack 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 8×8 square baking pan but if you are making it for a larger group it’s really easy to double it and bake in a 9×13 (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 chocolate sheet cake with extra fudgy chocolate buttercream makes it a chocolate lovers DREAM.

This buttercream uses a full 1/2 cup of cocoa, which is what makes it extra chocolatey (I’m not complaining).

a vegan sheet cake on parchment paper

Expert Tips

  • 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.
a vegan sheet cake with sprinkles and wacky cake frosting

Storage Instructions

How do I store this cake?

This wacky cake, like most chocolate snack 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?

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.

More Recipes You’ll Love

If you make this recipe, let me know how it went in the comments below, I’d love to hear from you! You can also tag me on Instagram or Facebook so I can check it out!

a piece of vegan sheet cake with wacky cake frosting
5 from 10 reviews

Chocolate Snack Cake

This super moist chocolate snack cake is so easy – its made in the same pan you bake it in! It’s topped with a smooth fudgy buttercream for extra chocolatey-ness.

Ingredients
 

Wacky Chocolate Cake

  • 1⅓ cup +1 tbsp (190 g) all-purpose flour
  • ¾ cup (160 g) granulated sugar
  • ¼ cup (25 g) cocoa powder
  • ¾ tsp salt
  • 1 tsp baking soda
  • 1 tsp baking powder
  • 1 tbsp white vinegar
  • cup canola oil (or other neutral oil)
  • 1 cup hot water

Wacky Cake Frosting (Fudgy Buttercream)

  • ¾ cup butter , (vegan or regular)
  • ½ cup cocoa powder
  • cup powdered sugar
  • ½ tsp vanilla extract
  • 1-1½ tbsp milk of choice (if needed), (vegan or regular)

Instructions
 

Chocolate Snack Cake

  • Preheat oven to 350°F. Lightly spray an 8×8 square baking pan with cooking spray.
  • Add the flour, sugar, cocoa powder, salt, baking soda, and baking powder and mix with a fork until any clumps are gone.
  • 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 Chocolate Frosting

  • Add butter to a bowl and slowly add in the powdered sugar, followed by cocoa powder, mixing until combined.
  • Add in the vanilla, followed by the milk. If the buttercream appears too thick, mix milk in a 1/2 tbsp at a time until it reaches the desired consistency. If it’s still too thick, add another 1/2 tbsp of milk.
  • Once the cake has cooled completely, spread the icing on the cake using a spatula. Slice and serve!

Notes

DOUBLING INSTRUCTIONS: You can easily double this recipe and make it in a 9×13 inch pan. Simply double all ingredient amounts 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.
STORAGE INSTRUCTIONS: Store the cake in an airtight container or tightly covered at room temperature for up to 4 days. Leftover buttercream can be frozen for up to 2 months in a sealed container.
Calories: 489kcal, Carbohydrates: 72g, Protein: 5g, Fat: 22g, Saturated Fat: 4g, Polyunsaturated Fat: 6g, Monounsaturated Fat: 11g, Trans Fat: 0.1g, Sodium: 488mg, Potassium: 155mg, Fiber: 4g, Sugar: 40g, Vitamin A: 719IU, Calcium: 42mg, Iron: 3mg
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The calorie information provided for this recipe is an estimate. The accuracy of the calories listed is not guaranteed.