Melt 4 tablespoons butter in the bottom of a large bowl; let cool.
Whisk in sugar, eggs, then 2 cups buttermilk.
Sprinkle surface of batter with salt, baking powder, and baking soda and mix thoroughly, scraping down bowl when you're done.
Add GF flours and mix well (no need to worry about overmixing GF flours).
Let batter rest about 10 minutes for better hydration of flours.
Heat an electric griddle or large skillet over medium heat.
Spoon batter onto the griddle, add blueberries, flip when bubbles appear on top, cook until golden underneath.
Transfer pancakes to a serving platter or keep warm in the oven.
Serve with powdered sugar, butter, maple syrup, or as desired.
