01 - Preheat oven to 350°F. Grease a standard 12-cup muffin tin or line with silicone muffin liners.
02 - In a large bowl, whisk eggs and milk together until the mixture is thoroughly blended.
03 - Fold in spinach, green onions (if used), feta, mozzarella or cheddar, salt, pepper, garlic powder, and nutmeg until evenly distributed.
04 - Divide mixture evenly among muffin cups, filling each about two-thirds full.
05 - Bake for 18 to 20 minutes until egg bites are set and lightly golden on the tops.
06 - Cool in the tin for 5 minutes, run a knife around each bite, and gently release. Serve warm or at room temperature.