Preheat the oven to 350°F (175°C).
Lightly grease a 12-cup muffin tin with oil spray, or use silicone liners to prevent sticking.
Prep your add-ins. Dice vegetables into small, even pieces so they cook quickly. If using mushrooms or onions, sauté them for a few minutes to remove excess moisture. Chop cooked proteins into bite-size pieces.
Vegetables: bell peppers, spinach, cherry tomatoes, red onion, mushrooms, broccoli, or zucchini, Cooked lean protein: diced turkey sausage, chicken sausage, turkey bacon, or cooked ground turkey
Whisk the eggs. In a large bowl, whisk 10–12 eggs with a pinch of salt and pepper.For extra protein and a lighter texture, whisk in 1/2–1 cup egg whites and 2–4 tablespoons of milk or almond milk.You can also separate some of the egg yolks and put them on top of the Muffins 3-4 Minutes before the end of baking. 12 Large eggs, 1 cup Egg whites, Seasonings: salt, black pepper, garlic powder, smoked paprika, red pepper flakes (optional), 3 tbsp Milk or unsweetened almond milk
Season well. Add 1/2 teaspoon garlic powder and 1/2 teaspoon smoked paprika. Adjust to taste with red pepper flakes if you like a little heat.
Seasonings: salt, black pepper, garlic powder, smoked paprika, red pepper flakes (optional)
Layer the fillings. Divide the chopped veggies and cooked protein evenly among the muffin cups, filling each about one-third to halfway full. Sprinkle cheese and herbs on top if using.
Cheese: shredded cheddar, mozzarella, feta, or goat cheese (optional), Seasonings: salt, black pepper, garlic powder, smoked paprika, red pepper flakes (optional)
Pour in the egg mixture. Carefully pour the eggs into each cup, leaving about 1/4 inch at the top to prevent overflow.
Bake for 18–22 minutes. The muffins are done when the centers are just set and a toothpick comes out clean.
They may puff up in the oven and settle slightly as they cool.
Cool before removing. Let the muffins rest in the tin for 5 minutes, then run a small spatula or knife around the edges to release. Move them to a wire rack to cool completely.
Serve or store. Enjoy warm right away, or cool and store for later. They pair nicely with hot sauce, salsa, or a dollop of Greek yogurt.