Mix the dry ingredients. Whisk the flour, sugar, baking powder, baking soda and salt together in a large bowl.
Make the batter. In a second bowl, whisk the buttermilk, eggs and vanilla, if using. Gradually whisk in the melted butter. Pour into the flour mixture and fold gently, scraping along the bottom of the bowl. Stop when the last dry streak of flour disappears. A few small lumps are fine.
Rest the batter. Let it stand for 10 minutes. Meanwhile, warm a large skillet or griddle over medium heat and brush it lightly with butter or oil.
Cook the pancakes. Scoop a scant ⅓ cup of batter per pancake onto the hot pan, leaving room to flip. Let each one spread on its own. Cook for 2–3 minutes, until the edges look set and bubbles near the rim pop and leave little holes.
Flip and serve. Slide a thin turner under each pancake and flip once. Cook for another 1–2 minutes, until the underside is golden and the centre feels springy. Repeat with the remaining batter, lightly greasing the pan between batches as needed. Serve warm with salted butter and maple syrup.