Why is the batter so thin?
Because this cake is playing the long game. The hot coffee (or hot water) loosens the batter and helps the cocoa fully hydrate, which bakes up into a moist, tender crumb. Thin batter here is a good sign.
Do I have to use coffee?
Nope. Use hot water if you prefer. Most people will not taste “coffee.” It mainly makes the chocolate taste more like chocolate. If you are very sensitive to coffee flavor, use hot water.
Can I make this as a 9x13 sheet cake?
Yes. Bake at 350°F for about 30 to 38 minutes. Start checking at 30. You want a toothpick to come out with a few moist crumbs, not wet batter.
Can I turn this into cupcakes?
Yes. Fill liners about 2/3 full and bake 18 to 22 minutes at 350°F.
What about 8-inch pans?
Also works. Use two 8-inch round pans and bake a little longer, usually 32 to 38 minutes. The layers will be thicker, so start checking at 32 minutes and go by the toothpick test.
How do I keep my layers from doming?
Make sure your oven is truly at 350°F, do not overmix, and use cake strips if you have them. Also, weigh your batter into the pans for even layers.
Can I use Dutch-process cocoa?
This recipe is designed for natural unsweetened cocoa (like Hershey’s). Dutch-process cocoa is less acidic, which can change how baking soda behaves and affect lift. This cake uses both baking soda and baking powder, so it can still work, but the texture and rise may be a little different. If natural cocoa is an option, it is the safest choice here.
How much frosting does this make?
Enough to frost a 2-layer 9-inch cake with a generous layer in the middle plus a classic coat on the top and sides. If you love super thick swirls, you may want 1.5x the frosting.