2 cups all-purpose flour
3 tablespoons granulated sugar
1 teaspoon baking powder
3/4 teaspoon fine salt
1/2 teaspoon baking soda
2 cups buttermilk
2 large eggs
4 tablespoons unsalted butter (1/2 stick), melted and slightly cooled
Vegetable oil
1 cup fresh or frozen blueberries
Butter and maple syrup, for serving

Place the flour, sugar, baking powder, salt, and baking soda in a large bowl and whisk until evenly combined. Place the buttermilk, eggs, and melted butter in a medium bowl and whisk until evenly combined. Add the buttermilk mixture to the flour mixture and stir with a spoon or rubber spatula until the flour is just incorporated and no streaks remain, about 20 strokes. (The batter will be lumpy.) Let rest for 5 minutes. Heat a large frying pan, seasoned cast iron skillet, or griddle over medium heat for about 4 minutes. Test to see if the pan is hot enough by sprinkling a few drops of water in it: If the water bounces and sputters, the pan is ready to use; if it evaporates instantly, the pan is too hot. When the pan is ready, use a paper towel to coat it with a thin film of vegetable oil.
Ladle the batter into the pan: 1/2 cup for large (6-inch) pancakes or 1/4 cup for smaller (4-inch) pancakes, leaving at least 1 inch in between. Evenly sprinkle each pancake with 1/8 cup berries for large and 1 T for small. Cook until little bubbles appear on the pancakes' surface and the bottoms are golden brown, about 3 to 4 minutes. Flip and cook the second side until the bottoms are golden brown, about 2 minutes more. Serve with butter and maple syrup.