Beat the eggs in a mixing bowl and season with salt, pepper, and garlic powder if desired.

Heat a non-stick skillet over medium heat. Add butter or olive oil to coat the pan.

Add the chopped spinach to the skillet and sauté for 1-2 minutes until wilted. Remove from the pan and set aside.

Pour the beaten eggs into the skillet, tilting to spread evenly. Cook until the edges start to set, then gently lift and let uncooked egg flow underneath.

Sprinkle crumbled feta cheese and cooked spinach over one half of the omelet.

Fold the omelet in half and cook for another 30 seconds to melt the cheese slightly.

Slide the omelet onto a plate and garnish with additional feta or red pepper flakes if desired. Serve immediately.