Combine flour, sugar, baking powder, baking soda and salt in a large bowl.
Make a well in the center; add buttermilk, melted butter, vanilla and egg.
Mix together until smooth; let rest ~10 minutes.
Preheat a nonstick pan or griddle on medium-low heat; lightly butter hot surface.
Pour ~⅓ cup batter onto the hot surface; let flatten; pour next batter ~3 inches from last; repeat until surface is covered.
When bubbles begin to appear and open on the surface, flip pancakes.
Work in batches until batter is used; serve pancakes immediately, or keep warm in a 250°F oven.
