Ensure the flour is sifted after measuring for a smooth batter. Use only full-fat buttermilk for best texture. All refrigerated ingredients should reach room temperature before beginning. To prepare ahead, wrap cooled layers in plastic wrap and store in the refrigerator for up to 2 days or freeze for up to 2 weeks. Thaw wrapped layers at room temperature. Once assembled, the cake can be stored covered in the refrigerator for up to 3 days or frozen for up to 2 months. Thaw overnight in the refrigerator and bring to room temperature before serving.