*No buttermilk? Add 1 teaspoon white vinegar to your half-cup measure. Fill it up the rest of the way with milk (I used whole milk, but any milk will work) and wait 5-10 minutes. You’ve got a homemade buttermilk stand-in! The acidity is important in this recipe because it reacts with the baking soda to help the cake rise.
Note: For whipped cream that holds up well in the refrigerator for a day or two, add 1/4 cup mascarpone cheese per cup of heavy cream. Details here!