Protein omelette with spinach

Ingredients:

• 4 tsp extra-virgin olive oil
• 1 small onion, finely chopped
• 4 plum tomatoes, finely chopped (about 1 1/2 cups)
• 1 package (280g) frozen chopped spinach, thawed and squeezed out of excess water
• 12 egg whites
• 2 tablespoons of water

Preparation:

1. Heat olive oil in a small skillet over medium heat. Add the onion, tomatoes, spinach, and a pinch of salt. Cook until the onion is soft, about 3-5 minutes. Season with pepper to taste, add another pinch of salt, and cook for another minute. Remove the spinach from the heat and transfer to a bowl. Cover and keep warm.
2. In a medium bowl, whisk the egg whites, water, and a pinch of salt and black pepper until foamy. Lightly spray a medium nonstick skillet or omelet pan with cooking spray and heat over medium heat. Add 1/4 of the egg whites, stirring to evenly coat the bottom of the pan. Cook until the whites are set, about 1 1/2 to 2 minutes. Using a rubber spatula, lift the omelet and allow the runny raw egg to drip down. Spoon 1/4 of the spinach mixture onto half of the omelet, fold it in half, and transfer to a serving plate. Repeat with the remaining egg whites and spinach mixture.