Preheat the oven to 170° C (350° F). Sprinkle 4 muffin pans with olive oil; set aside. In a large bowl, whisk together the eggs, milk, onion, red pepper, parsley, red pepper flakes and black pepper, until well combined. Pour the egg mixture into the muffin pans. Bake 18 to 20 minutes till the muffins are puffed and golden.