– 2 cups granulated sugar – 2 cups all-purpose flour – 1/2 teaspoon salt – 1/2 cup butter (1 stick) – 1/2 cup vegetable oil – 1/4 cup unsweetened cocoa powder – 1 cup water – 1/2 cup buttermilk – 1 teaspoon baking soda – 2 eggs, room temperature – 1 teaspoon vanilla extract Chocolate Frosting: – 1/4 cup milk – 1 cup granulated sugar – 1/4 cup butter (1/2 stick) – 1/2 cup semi-sweet chocolate chips – 1 cup mini marshmallows
Dissolve baking soda in the buttermilk. Stir together until the buttermilk becomes foamy. Pour the buttermilk into the cake batter mixture. Add in the eggs and vanilla. Whisk or mix together until all ingredients are well incorporated and smooth. Pour the batter into the prepared pan.