Prep the veggies. Finely chop bell pepper and onion, slice mushrooms thin, and roughly chop spinach. Smaller pieces cook quickly and fold more easily into the omelet.

Beat the eggs. Crack eggs into a bowl with a pinch of salt and pepper. Whisk until the mixture looks uniform and slightly frothy—this helps make the omelet fluffy.

Warm the pan. Heat a nonstick skillet over medium heat. Add olive oil or butter and swirl to coat the surface evenly.

Sauté the vegetables. Add onion and bell pepper first; cook 2–3 minutes until slightly softened. If using mushrooms, add them now and cook another 1–2 minutes. Stir in tomatoes and spinach last, cooking just until the spinach wilts. Season lightly with salt and pepper.

Transfer veggies briefly. Slide the cooked vegetables onto a plate. Wipe the pan if it looks wet, then add a tiny splash of oil or butter back to the pan.

Pour the eggs. Add the beaten eggs and tilt the pan to spread them evenly. Let the edges set for about 20–30 seconds.

Add the cottage cheese. Spoon cottage cheese in small dollops over one half of the omelet. Spread the cooked veggies on top of the cottage cheese. Sprinkle herbs and any optional cheese.

Lower the heat. Reduce to medium-low. Use a spatula to gently loosen the edges, letting a little uncooked egg flow underneath. Cook until the top is just slightly glossy.

Fold and finish. Carefully fold the omelet in half over the filling. Cook another 30–60 seconds until warmed through and lightly set. Avoid overcooking; you want tender eggs, not rubbery ones.

Plate and garnish. Slide onto a plate. Add extra herbs, a pinch of red pepper flakes or paprika, and a few avocado slices if you like. Serve hot.