Step 1

Heat the oven and skillet to 375°F. Arrange a rack in the upper third of the oven and heat the oven to 375°F. Place a 10-inch cast iron skillet or oven-safe nonstick pan in the oven while it heats.

Step 2

Mix the dry ingredients. Whisk 1 1/4 cups all-purpose flour, 2 tablespoons granulated sugar, 2 teaspoons baking powder, 1/2 baking soda, and 1/2 teaspoon kosher salt together in a large bowl.

Step 3

Melt the butter. Microwave 2 tablespoons unsalted butter in a separate smaller microwave-safe bowl or large measuring cup in 10-second bursts until melted, 30 to 40 seconds.

Step 4

Mix wet ingredients. Add 1 1/4 cups buttermilk to the melted butter. Then separate 2 eggs, collecting the egg whites in the measuring cup used for the buttermilk. Add the egg yolks to the melted butter and whisk to combine.

Step 5

Combine the wet and dry ingredients. Pour the buttermilk mixture into the flour mixture and stir with a spatula until most of the flour is moistened. Add the egg whites and fold in just until incorporated, but do not overmix.

Step 6

Rest the batter. Set the batter aside for 10 minutes.

Step 7

Melt the butter in the skillet. Cut the remaining 2 tablespoons unsalted butter into 4 pieces. Take the preheated skillet out of the oven and add the butter. Swirl the pan until the butter melts and coats the bottom and sides.

Step 8

Add the batter to the pan. Transfer the pancake batter to the pan and spread into an even layer.

Step 9

Top with blueberries. Sprinkle 1 1/2 cups blueberries evenly over the pancake batter.

Step 10

Bake the pancake. Bake the pancake until puffed and golden brown, 25 to 30 minutes.

Step 11

Serve the pancake. Cut into wedges and serve with maple syrup and more berries.