Whisk together in a large bowl:
1 1/2 cups all-purpose flour
3 tablespoons sugar
1 1/2 teaspoons baking powder
1/2 teaspoon salt
1/2 teaspoon baking soda
Whisk together in another bowl:
1 1/2 cups buttermilk
3 tablespoons unsalted butter, melted
2 large eggs
1/2 teaspoon vanilla (optional)
Pour the wet ingredients over the dry ingredients and gently whisk them together, mixing just until combined.
Spoon 1/3 cup batter onto the preheated griddle for each pancake, nudging the batter into rounds. Cook until the top of each pancake is speckled with bubbles and some bubbles have popped open, then turn and cook until the underside is lightly browned. Serve immediately or keep warm in a 200 degree oven while you finish cooking the rest.