Whisk batter. If necessary, thin with an additional tablespoon of milk (batter should have consistency of thin cream). Mist a 10-inch nonstick skillet with cooking spray and warm over medium heat. When pan is hot, ladle in 1/4 cup of batter. Quickly tilt skillet so batter coats surface in a thin layer. Cook until edges begin to brown, about 2 minutes. Lift edge of crepe and, using your fingers, carefully flip. Cook for 30 seconds; transfer to a plate. Cover with a clean kitchen towel. Repeat with remaining batter, misting skillet with cooking spray between crepes as necessary.