Preheat oven to 275°
Grease a 24-cup mini-muffin pan (preferably a non-stick pan) - these are REALLY sticky!
In a large bowl, whisk together the flour, baking powder, Italian seasoning, salt and red pepper flakes (if using)
Whisk in the milk and egg.
Stir in the mozzarella, parmesan and pepperoni; let stand for 10 minutes.
Stir the batter and divide among the mini-muffin cups.
Bake until puffed and golden, 20 to 25 minutes.
Meanwhile, microwave the pizza sauce until warmed through.
Serve the puffs with the pizza sauce for dipping.