This is an absolutely must have recipe for so many reasons. For one, it’s truly so delicious, possibly one of the best chocolate cake recipes. Two, it’s made in one pot in minutes, so your kitchen won’t be a complete disaster afterwards. Three, sheet cakes are amazing crowd pleasers as well as are extremely easy to transport (so much easier than cupcakes) so you can take it anywhere!
Special thanks goes out to my friend Jess who convinced me to modify my treasured chocolate cake recipe into this one. She made such a fantastic point, that although my original chocolate cake is quite spectacular, having another easier and quicker version would really benefit many homecooks, especially when dessert is needed on short notice and for a larger crowd. She is completely right.
So in this preparation, you do not need a mixer, you do not need a double boiler, you don’t need to dirty a ton of pots. You need one pot, just minutes of your time to put the cake together and 20 minutes to bake it. That’s it. And the result – spectacular, rich, moist and ultra delicious cake!
I also adjusted the proportions of the original cake slightly, to account for a larger baking surface and a thinner cake.
One last thing, I’m providing 2 icing options. My classic chocolate buttercream works beautifully with this cake. However, thick fudgy pourable icing is also a fantastic choice. It’s easier and quicker, and you can pour it over still warm cake without having to worry too much about cooling the cake completely. The choice is completely yours!
Let’s get cooking!
No buttermilk? No problem. Put 2 tsp of white vinegar or fresh lemon juice in your 1/2 cup measure. Fill the rest with milk. Allow it to sit at room temperature for 10 minutes to thicken and turn into "homemade buttermilk"
Preheat oven to 350.
Line large rimmed baking sheet with parchment paper, allow the sides of the parchment to overhang so that the cake could be easily lifted out after it's baked. I'm using 13x18 half sheet, which is ideal for this cake. But regular jelly roll rimmed baking sheet will work.
Melt butter over low heat in a medium pot. Once melted, remove from heat.
Add chopped chocolate and allow to sit for a minute. Then stir with a rubber spatula until chocolate has melted. Add cocoa powder and stir more until smooth.
Mix in coffee, sugar, salt and vanilla with a whisk.
You do not need to let this mixture cool completely, however, allowing it to cool down a little bit is a good idea.
Add buttermilk and eggs, making sure to whisk well immediately after adding, to gradually warm the eggs and ensure they do not scramble in your still warm chocolate mixture.
Sift flour combined with baking powder and baking soda directly into your batter. Mix it with a whisk until completely combined. Then mix with a few more vigorous strokes of a whisk to aerate the batter a bit.
Pour into prepared baking sheet. Bake in preheated oven for about 20 minutes until the cake is firm and a toothpick inserted in the centre comes out with just a few crumbs but not wet/liquid batter. If you press down on the cake, your finger should still be able to leave an indentation, a sure sign your cake is plenty gooey and not overbaked.
The internal temperature measure that I love to use with baking will not work as well here, since the cake is so thin and the reading may not be accurate – toothpick will work just fine!
Remove the cake from the oven and allow to cook completely before icing.
In a bowl of a stand mixer, mix all of the icing ingredients on low at first (to avoid all of the sugar and cocoa from splashing everywhere.) When everything is incorporated, increase the speed to high and beat for a few minutes until fluffy and lightened in colour. Remember to adjust consistency of the buttercream with more heavy cream, if needed. Stop the mixer, scrape the sides of the bowl and beat on high for another minute or two.
Lift the cooled cake out of the pan by the sides of the parchment paper. Spread 2/3 of the buttercream evenly over cake. Pipe the remainder of the icing in a decorative manner, if desired.
Slice the cake into desired number of squares, I sliced into 32.
Ingredients
Directions
Preheat oven to 350.
Line large rimmed baking sheet with parchment paper, allow the sides of the parchment to overhang so that the cake could be easily lifted out after it's baked. I'm using 13x18 half sheet, which is ideal for this cake. But regular jelly roll rimmed baking sheet will work.
Melt butter over low heat in a medium pot. Once melted, remove from heat.
Add chopped chocolate and allow to sit for a minute. Then stir with a rubber spatula until chocolate has melted. Add cocoa powder and stir more until smooth.
Mix in coffee, sugar, salt and vanilla with a whisk.
You do not need to let this mixture cool completely, however, allowing it to cool down a little bit is a good idea.
Add buttermilk and eggs, making sure to whisk well immediately after adding, to gradually warm the eggs and ensure they do not scramble in your still warm chocolate mixture.
Sift flour combined with baking powder and baking soda directly into your batter. Mix it with a whisk until completely combined. Then mix with a few more vigorous strokes of a whisk to aerate the batter a bit.
Pour into prepared baking sheet. Bake in preheated oven for about 20 minutes until the cake is firm and a toothpick inserted in the centre comes out with just a few crumbs but not wet/liquid batter. If you press down on the cake, your finger should still be able to leave an indentation, a sure sign your cake is plenty gooey and not overbaked.
The internal temperature measure that I love to use with baking will not work as well here, since the cake is so thin and the reading may not be accurate – toothpick will work just fine!
Remove the cake from the oven and allow to cook completely before icing.
In a bowl of a stand mixer, mix all of the icing ingredients on low at first (to avoid all of the sugar and cocoa from splashing everywhere.) When everything is incorporated, increase the speed to high and beat for a few minutes until fluffy and lightened in colour. Remember to adjust consistency of the buttercream with more heavy cream, if needed. Stop the mixer, scrape the sides of the bowl and beat on high for another minute or two.
Lift the cooled cake out of the pan by the sides of the parchment paper. Spread 2/3 of the buttercream evenly over cake. Pipe the remainder of the icing in a decorative manner, if desired.
Slice the cake into desired number of squares, I sliced into 32.
Variation for thick fudgy pourable icing. You can make this instead of the buttercream:
In a medium sauce pan, melt 14 TBSP of unsalted butter over low heat; remove from heat once melted. Add heaping 1/4 cup of cocoa powder and stir. Stir until it forms into thick ganache-looking concoction. Add 1/4 tsp kosher salt, 6 TBSP milk, 1 tsp vanilla and 3 cups powdered sugar. Whisk well to combine. The consistency should be thick but pourable; if your icing is too thin, you may need to add a bit more powdered sugar. Pour over your cooled or still warm sheet cake. Feel free to add chopped toasted walnuts or pecans for another layer of textures and flavours. It’s so delicious!
This is literally one of the best recipes I’ve tried so far.
The cake is excellent, it’s sweet, moist and chocolatey.
It’s easy and simple yet super delicious!
Thank you for sharing!
Thanks so much M. I’ve been working on this recipe for sooooooooo long xoxo
This recipe is genius! By far the easiest homemade cake I have ever made! Currently making for my second time to cure my chocolate craving for the next few days
Aww Lauren, thanks so much hun!!! “Genius” – I love that word to describe this cake! So happy you enjoyed! xoxo