Preheat oven to 350 degrees.
Prepare cake pans with Crisco and lightly dust with flour. I prefer the Wilton Quick Release product instead of the traditional Crisco/Flour prep.
I prefer to make my own sour milk. I think the vinegar does something to the recipe and makes it more moist or something. To do so, in a glass measuring cup, add 2 tbs of distilled vinegar then add your milk (I used skim milk) and measure to 2 cups. Whisk, and let stand for 20 minutes. I whisk again before adding it to my mixing bowl.
Put all ingredients into a mixing bowl. With the PADDLE attachment, mix together for 2 minutes. Scrape down the side and bottom of the bowl to ensure all ingredients are mixed well.
FOR SHEET CAKES: Pour into your pan and bake for 25-30 minutes, or until a toothpick inserted into the center of the cake comes out with moist crumbs on it, or use the Wilton's baking guide.
FOR ROUND CAKES: Pour into your prepared pan, bake for 35-40 minutes or use the Wilton's baking guide, or until a toothpick inserted into the center of the cake comes out with moist crumbs on it (not gooey uncooked batter).
FOR CUPCAKES: Pour into tins, bake for approximately 18 minutes or until a toothpick inserted into the center of the cupcake comes out with moist crumbs on it (not gooey uncooked batter).
For a deeper, richer chocolate taste, reduce the buttermilk by 1/4 cup and replace it with a 1/4 cup of brewed coffee. I personally think with 1 cup of cocoa, the recipe already has a rich chocolate taste.
I like to experiment with the extracts. If making a filling such as raspberry, replace the vanilla with raspberry extract. Experiment with different flavors and combinations for a different taste. Chocolate cake with a hint of orange flavoring is to die for.