This is a recipe by Sky-High Cakes. The chocolate cake is very good and moist, and easy. There aren't really any tricky tricks like melting chocolate to make it gruesome. It is a good recipe for the chocolate cake and vanilla frosting combination.
For the cake:
1 cup unsweetened cocoa powder
1 1/4 cup hot water
3 cups packed brown sugar (helps keep it moist)
2 2/3 cup cake flour (I used 2 1/4 AP flour and the rest cornstarch because I was out of cake flour. It worked very well, according to my little test cupcake.)
1 1/2 t baking soda
3/4 t salt
2 sticks plus 2 T unsalted butter, softened.
1 1/2 t vanilla
3/4 cup cold water
Preheat the oven to 325 F. Butter and line 3 8 or 9-in round cake pans with parchment circles.
Place the cocoa powder in a medium bowl and add the hot water. Whisk til smooth and set aside to cool.
In the bowl of an electric mixer, combine the brown sugar, flour, baking soda and salt. With the mixer on low, blend to mix. Add the butter and the dissolved cocoa and beat briefly to blend. Then raise the speed to medium and beat until fluffy, about 2 minutes. (See? So easy. No "add in alternating additions" stuff).
In a medium bowl, whisk the eggs, vanilla and cold water until blended and added gradually to the batter, scraping the bowl as needed. Divide the batter among your three pans and smooth the tops.
Bake for 35-40 min (it will be less if you use 9-in pans, so check early). It's done when the tester comes out almost clean.
Let cool for 15 minutes in the pan and then cool completely on wire racks
Make your brown sugar frosting.
boiling the sugar and water
To me, brown sugar frosting sounds homey and rich and maybe a little caramelly, but it mostly tasted like regular vanilla buttercream. Next time I'm going to try using dark brown sugar, or maybe even muscovado sugar to give it more depth. Or I could try making brown sugar caramel frosting. Or adding a spice like cinnamon, or even some citrus zest. The possibilities are endless.
Brown Sugar Buttercream:
5 egg whites
1 1/4 cups packed brown sugar
1/4 cup water
1 pound (4 sticks) unsalted butter, softened but not mushy.
Place the egg whites in the bowl of an electric mixer fitted with the whisk attachment.
In a medium saucepan, combine the brown sugar and water. Bring to a boil and cook until the temperature reaches 238 F on a candy thermometer.
A few minutes into the boiling of the sugar, start beating the eggwhites; beat until soft peaks form and then, while the whisker is whisking, slowly pour in the hot sugar syrup. Beat at med-high until the sides of the bowl aren't hot anymore.
Drop the speed to medium-low and add the butter one tablespoon at a time. When all the butter is added, raise the speed to medium and beat the frosting until smooth. Don't worry if it appears to curdle, just keep beating.
I froze my layers a couple hours beforehand, which always makes frosting easier. It makes refrigerating between the crumb coat and the final coat almost unnecessary, especially with this type of frosting.
To decorate, I sprinkled turbinado sugar on top and piped chocolate ganache around in loopy loops.