Potluck Buttermilk Chocolate Sheet Cake
This cake is baked in an easy-to-carry-along 9x13 inch pan. It also tastes great on Day 2, which makes it the perfect make-ahead and take dessert.
Servings 12
Ingredients
- 2 sticks 230 grams unsalted butter
- ⅓ cup unsweetened natural cocoa powder Scharffen Berger works well
- 1 cup water
- 2 cups sugar 390 grams
- 2 cups flour sift after measuring (250 grams)
- 1 teaspoon salt
- 2 teaspoons baking soda
- 2 large eggs room temperature
- ½ cup buttermilk room temperature
- 2 teaspoons vanilla
Buttermilk Icing
- 1 ½ cups powdered sugar sifted
- ½ teaspoon salt omit if using salted butter
- ¾ cup unsalted butter
- 4 ½ ounces buttermilk
- ¼ teaspoon vanilla
- 7 ½ tablespoons cocoa
Instructions
- Preheat oven to 350 degrees. Grease a 9x13 inch baking pan. If using a disposable pan, you can skip this step.
- In a saucepan, melt the butter. Add the cocoa powder and stir until smooth, then stir in the water. Remove from heat and set aside.
- Mix together flour, sugar, salt and baking soda. Sift if necessary.
- In a mixing bowl or in a 2 cup glass measure, whisk together eggs, buttermilk and vanilla.
- Add cocoa mixture and buttermilk mixture to dry ingredients and stir until everything is well mixed, then beat 30 strokes with a big spoon or a heavy duty scraper.
- Pour into the pan and bake for about 30 minutes or until cake springs back when touched.
- Let the cake cool while you make the icing.
- To make the icing, melt butter in a saucepan set over low heat. Add the cocoa and whisk until smooth, then add the buttermilk and vanilla and whisk until smooth.
- Put the confectioners' sugar and salt (if using) in a food processor.
- With motor running, pour cocoa mixture through feed tube and process only until smooth.
- Pour this mixture over the cooled cake. Let cool down slightly, then put the whole cake in the refrigerator to help set the icing.
- Once the cake is chilled and set, you can take it out and store it covered at room temperature.
Notes
Sifting flour isn't always necessary, but in this recipe it's a good idea to do it to help prevent lumps. You'll also need to sift the confectioners' sugar.
In my experience, the icing is better when I use a food processor. However, you could probably get away with just putting the confectioners' sugar and salt in a bowl, pouring the chocolate in and mixing vigorously.