Preheat your broiler.

Whisk the eggs, 1/2 tsp salt, and pepper in a bowl.

Preheat a 9-10 inch nonstick skillet over medium heat and spray with olive oil or cooking spray.

Add the spinach and the remaining 1/2 tsp salt, and cook 3-4 minutes, or until the spinach wilts.

Add the tomatoes and eggs, and stir gently with a rubber spatula.

Continue to cook over medium heat until set slightly, 5-6 minutes, stirring and scraping the bottom of the pan with the spatula every minute or two.

Scatter the cheese over the top, cover, and cook for 6-7 minutes.

Once the eggs are nearly cooked through, place under the broiler for 3-4 minutes, or until the eggs are fully set and the top has browned.

Use a spatula to loosen the frittata from the pan, and slide out onto a cutting board or plate in order to slice and serve.