Preheat the oven to 350°F. Butter and flour two 8-inch or 9-inch round cake pans. Set aside.
In the bowl of a stand mixer, cream together the butter, sugar, brown sugar and flavorings. Cream for 2-3 minutes until combined. Add the eggs 1 at a time beating well after each.
Use a whisk to sift together the flour, cocoa, baking soda, baking powder and salt. Add to the creamed mixture alternately with the buttermilk starting and ending with flour.
After all of the dry ingredients have been added stop and scrape the sides and bottom of the bowl. Beat the batter for 30 seconds on medium-high until creamy. Divide between the pans.
Place into the oven and bake for 30-40 minutes or until a toothpick inserted into the center comes back clean. Cool in the pan for 30 minutes until the sides release from the pan.
Carefully remove from the pans and cool completely on a cooling rack. Frost as desired.
Adapt the Baking Time: Bake time varies by shape, please adjust using the toothpick method to check the middle for doneness: Rounds 30-40 minutes, Cupcakes 20-25 minutes, Sheet Cake 30-40 minutes, Mini Cupcakes 8-10 minutes.
How Do You Make Homemade Buttermilk? To make your own buttermilk, to each one cup of whole milk add one tablespoon of fresh lemon juice or white vinegar. Let it stand on the counter for 5-10 minutes then stir and proceed with the recipe.