Heat griddle to 375 degrees. If you plan to keep pancakes warm in the oven, heat oven to 175 degrees.
Whisk together flour, baking powder, baking soda, salt, and sugar in a medium bowl.
Add egg, buttermilk, and 2 tablespoons butter using a whisk. Do not over mix; the batter should have small lumps.
Test griddle by sprinkling a few drops of water on it. If water bounces and spatters off griddle, it is hot enough. Using a pastry brush, brush remaining 1/2 teaspoon of butter onto griddle. Wipe off excess.
Using an ice cream scoop or ladle, pour pancake batter (about half a cup), 2 inches away from one other. When pancakes have bubbles on top and are slightly dry around edges, about 21/2 minutes, flip over. Cook until golden on bottom, about 1 minute.
Work in batches, keeping finished pancakes in the oven. Serve warm with your favorite toppings!