Instructions:

Preheat oven to 325°F (163°C). Grease and flour two 9-inch round cake pans (or a 9×13 pan or bundt pan).

Cream butter and sugar: In a large bowl, beat the butter and sugar together until pale and fluffy (about 4–5 minutes).

Add eggs and vanilla: Beat in eggs one at a time, then add vanilla extract.

Mix dry ingredients: In a separate bowl, whisk together cake flour, baking powder, and salt.

Combine wet and dry: Add flour mixture to the butter mixture alternately with buttermilk and sour cream, beginning and ending with flour. Mix just until combined — don’t overbeat.

Bake: Divide the batter evenly between pans and bake for 30–35 minutes (or 45–55 minutes if using a bundt or 9×13) or until a toothpick comes out clean.

Cool in pans for 10 minutes, then turn out onto wire racks to cool completely.

Optional: Vanilla Buttercream Frosting
Beat butter until creamy.

Gradually add powdered sugar, beating well.

Mix in vanilla and enough cream/milk to reach a spreadable consistency.

Frost the cooled cake and enjoy!