Makes 1 omelet (2 to 4 servings)
1. In a mixing bowl, combine the eggs, milk, salt, and pepper. Beat with a whisk until combined and then stir in the tomatoes and cheese.
2. Heat the butter or oil in a small nonstick sauté pan over medium heat.
3. Add the egg mixture to the hot pan and use a heat-resistant rubber spatula or wooden spoon to gently stir and evenly spread the ingredients. Cook until the eggs are nearly set, about 30 seconds.
4. Use a pancake spatula to flip the eggs over and cook until the eggs are fully cooked, about 1 minute.
5. Transfer the finished omelet to a plate and cut into wedges to serve.
You could also add other ingredients, such as ham, bacon, and peppers or other vegetables, to the omelet.