Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Combine the first 7 ingredients in a medium bowl, stirring with a whisk.
Combine buttermilk, butter, and egg in a small bowl. Add to flour mixture, stirring just until moist.
Heat a nonstick griddle over medium heat. Coat pan with cooking spray. Spoon about 2 1/2 tablespoons batter per pancake onto griddle. Turn pancakes over when tops are covered with bubbles; cook until bottoms are lightly browned.