1. Heat oven to 400°F. Spray 9 cups of a 12-cup muffin pan with cooking spray.
2. In a medium bowl, combine flour, Parmesan, and sugar and whisk until just blended. Add sour cream and egg and stir until just combined.
3. Spoon batter into prepared pan and bake until springy to the touch, 18 to 20 minutes. Let cool 10 minutes before serving.