Preheat oven to 350°F. Line a 12-cup muffin tin. Whisk flour, baking powder, baking soda, and salt. In a separate bowl, beat butter and sugar until fluffy. Beat in eggs and vanilla. Add dry mix and buttermilk in batches, mixing until just combined. Fill liners 2/3 full. Bake 18–22 min until golden. Cool 10 min.