2 cups all-purpose flour
2 teaspoons baking powder
1 teaspoon baking soda
1/2 teaspoon kosher salt, or slightly less table salt
3 tablespoons sugar
2 large eggs, lightly beaten
3 cups buttermilk
4 tablespoons unsalted butter, melted, plus 1 tablespoon extra for brushing griddle
1 cup blueberries, fresh or frozen and thawed (optional)
1. Preheat an electric griddle to 375°F, or place a griddle pan or cast-iron skillet over medium-high heat. Whisk together the flour, baking powder, baking soda, salt, and sugar in a medium bowl. Add the eggs, buttermilk, and 4 tablespoons melted butter, and whisk to combine. The batter should have small to medium lumps.
2. Test the griddle by sprinkling a few drops of water on it. If the water bounces and spatters, the griddle is hot enough. Using a pastry brush, brush the remaining 1/2 teaspoon butter onto the griddle. Wipe off the excess with a folded paper towel.
3. Using a 4-oz. ladle, about 1/2 cup (for a 6-inch pancake), pour the batter in pools 2 inches apart. If you wish to make blueberry pancakes, arrange a handful over the cooking pancake, pressing them in slightly. When the pancakes have bubbles on top and are slightly dry around the edges, about 2 1/2 minutes, flip over. If any batter oozes or blueberries roll out, push them back under with your spatula. Cook until golden on bottom, about 1 minute.
4. Repeat with the remaining batter. You can keep the finished pancakes on a heat-proof plate in the oven at 175°F. Serve warm.