Combine 2 cups cornmeal mix and next 2 ingredients; make a well in center of mixture.
Whisk together eggs, 2 1/4 cups buttermilk, and 1/3 cup melted butter. Add to cornmeal mixture, stirring just until moistened.
Heat cast-iron cornstick pans in a 425° oven 5 minutes or until hot. Remove pans from oven, and coat evenly with cooking spray.
Spoon batter into hot pans.
Bake at 425° for 10 to 12 minutes or until lightly browned. Remove from pans immediately.