Steps
1. Heat a non-stick pan over medium heat.
2. Crack the eggs into a bowl and whisk in the milk.
3. Spread the onions and tomatoes over the surface of the pan and cook for 1 minute.
4. Pour the egg mixture over the vegetables and cook until the eggs are slightly set.
5. Sprinkle the cheese over the top.
6. Using a spatula, carefully fold over the eggs into a semi-circle.
7. Cook for an additional 3 minutes or until the cheese is melted and the eggs are cooked through.
8. Serve the Tortilla de Queso warm.