Adapted from Summer Stone's recipe to make it sturdier for stacking
Two 8-inch cake pans
57gDutch processed cocoa powder
300 mlhot water plus 1 tbsp espresso powder
15mlvanilla extract(1 Tbsp)
5gbaking powder(1 tsp)
9 gbaking soda(1½ tsp)
Preheat oven to 350°F. Spray two 8-inch round cake pans with baking spray or grease and flour. Line bottom with parchment paper and for extra sharp sides -- line the sides as well.
In a large microwave safe bowl, melt butter and chocolate. Heat butter and chocolate for one minute followed by 30-second intervals, whisking until completely melted.
Whisk in sugar and then cocoa powder until fully incorporated. Gradually add hot coffee, whisking until smooth. Add vanilla and then the eggs one at a time.
In a mixer bowl combine flour, baking powder, baking soda and salt and mix with the flat beater until combined, about 30 seconds. With the mixer on low speed, gradually pour in the chocolate mixture. Once it is all added, beat on medium-high speed for one minute. Scrape down the sides and bottom of the bowl and and beat for 30 seconds more until smooth.
Pour into cake pans ( I scale to 800g) and bake for 35-40 or until a cake tester or toothpick comes out completely clean. Cool for 10 minutes then turn out of the pans.