01 - Whisk eggs, milk, salt, pepper, and nutmeg in medium bowl until fully blended.
02 - Melt butter in nonstick skillet over medium heat. Add shallot and cook 1 minute until fragrant.
03 - Stir in spinach and cook 1-2 minutes until wilted.
04 - Pour egg mixture over spinach. Cook undisturbed 1-2 minutes until edges begin to set.
05 - Lift edges with spatula, allowing uncooked egg to flow underneath. Cook 1-2 minutes until almost set.
06 - Sprinkle crumbled feta evenly over half the omelet.
07 - Fold omelet in half with spatula. Cook 1 minute until feta warms through.
08 - Slide onto plate and serve immediately.