- 1/2 cup unsalted butter, room temperature, plus more for pan
- 1 3/4 cups cake flour (not self-rising)
- 2 teaspoons baking powder
- 1/2 teaspoon salt
- 1 cup sugar
- 3 large eggs, room temperature
- 1 teaspoon pure vanilla extract
- 2/3 cup buttermilk, room temperature
- 1/4 cup plus 1 tablespoon cocoa powder
- Sieve and Whisk together the cake flour, baking powder, and salt; set aside.
- In the bowl, beat the butter and sugar until light and fluffy, about 5 minutes. Add eggs, one at a time, beating until combined after each addition and scraping down the sides of the bowl as needed. Mix in vanilla.
- Add flour mixture in 2 batches, alternating with the buttermilk and beginning and ending with the flour. Set aside 1/3 of the batter.
- In a bowl, mix cocoa and 1/4 cup plus 2 tablespoons boiling water with a rubber spatula until smooth. Add the cocoa mixture to the reserved cake batter; stir until well combined.
- Spoon batters into the prepared pan in 2 layers, alternating spoonfuls of vanilla and chocolate to simulate a checkerboard.
- To create marbling, run a knife (or wooden skewer) through the batters in a swirling motion.
- Bake in microwave (medium 5+3+2),test using a tooth pick..if it comes out clean or the cake springs back on touch the cake is cooked
- .Allow to stand in oven for 10-15 minutes(it will continue to cook with the temperature inside the microwave). Transfer pan outside to cool for 20-25 minutes.
- Invert the cake .If frosting is required you can do so else cut in slices and enjoy. Cake can be kept in an airtight container at room temperature up to 3 days.