Mix all of the dry ingredients in a resealable plastic bag, and set aside until ready to prepare muffins.
Preheat oven to 400 degrees. Butter a muffin tin, and set aside.
Place the dry-ingredient mixture in a medium bowl. Add eggs, buttermilk, and melted butter. Stir to combine; mixture should be lumpy.
Spoon mixture evenly into prepared muffin tin. Bake until golden, 12 to 15 minutes. Remove from oven and serve.