Whisk eggs in a bowl with pepper, turmeric powder and chili flakes and set aside.
Prepare your muffin tin or baking dish with cooking spray/liners.
Add the chopped veggies to the muffin tin or baking dish and spread evenly. Then pour the egg mixture into the baking dish or muffin tin. If using a muffin tin, fill cups about ¾.
Bake for 15-20 minutes until just set. There should be no jiggle in the center of the egg cups/baking dish.
Let cool before removing the egg from the dish/tin. If using a baking dish, slice the egg frittata into four pieces. Store egg cups/frittata slices in an airtight container in the fridge for up to four days.