Mix the dry ingredients: In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt until evenly combined.
Combine the wet ingredients: In a separate bowl, whisk buttermilk, egg (if using), melted butter, and vanilla extract until smooth.
Combine wet and dry: Pour the wet ingredients into the dry ingredients. Using a spatula, gently stir until just blended; avoid overmixing. A few lumps are okay; they’ll cook out and keep the pancakes fluffy.
Heat the pan: Heat a non-stick griddle or skillet to a medium temperature. Apply a little oil or butter.
Cook the pancakes: Scoop ¼ cup of batter per pancake onto the hot skillet. Cook for 2-3 minutes on the first side until bubbles form on the surface and the edges look set. Flip and cook for 1-2 minutes on the other side until golden brown.
Serve warm: Stack the pancakes on a plate and serve with your favorite toppings (see “What Toppings Go on Buttermilk Pancakes”).