Preheat an electric griddle to 375°F. Whisk together the flour, baking powder, baking soda, salt, and sugar in a medium bowl. Add the beaten egg yolks to the buttermilk. Add the 4 tablespoons melted butter to the dry ingredients and whisk to combine. Add the wet ingredients to the dry and combine. The batter should have small to medium lumps. Finally fold in the whipped egg whites.

Test the griddle by sprinkling a few drops of water on it. If the water bounces, it's ready. Butter the griddle to prepare for the batter.

Using a 1/2 cup, scoop and pour the batter onto the griddle about 2 inches apart. To make blueberry pancakes, hand place about 5 or more blueberries into each cooking pancake, pressing each one in slightly. When the pancakes have bubbles on top and are slightly dry around the edges, about 2 1/2 minutes, they're ready to 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.

Repeat with the remaining batter. Serve warm.