01 - Preheat oven to 350°F. Lightly grease a 12-cup muffin tin or line with silicone muffin liners.
02 - In a large mixing bowl, whisk together the eggs and milk until fully combined and smooth.
03 - Fold in spinach, green onions if using, crumbled feta, shredded mozzarella or cheddar, salt, black pepper, garlic powder, and nutmeg. Stir to ensure even distribution.
04 - Divide the egg mixture equally among the muffin cups, filling each about two-thirds full.
05 - Transfer muffin tin to oven and bake for 18 to 20 minutes, until egg bites are set and tops are lightly golden.
06 - Allow egg bites to cool in the tin for 5 minutes. Loosen each egg bite by running a knife around the edges and carefully lift out. Serve warm or at room temperature.