Add milk, egg, finely diced onion, Italian seasoning, minced garlic, salt, pepper, and red pepper flakes to a large mixing bowl. Using a wooden spoon, stir until the ingredients are incorporated. Let the mixture sit for 5 minutes.
1/4 cup Milk, 1 Egg, 1/4 cup Finely Diced Onion, 2 teaspoon Italian Seasoning, 2 cloves Minced Garlic, 3/4 teaspoon Salt, 1/4 teaspoon Red Pepper Flakes