frittata

1 tablespoon extra-virgin olive oil 1 small onion, sliced 2 cloves garlic, minced 1 package (10 ounces) frozen spinach, thawed and well-drained 2 large eggs 3 egg whites 1/3 cup fat-free evaporated milk 1/2 cup shredded reduced-fat mozzarella cheese SALSA: 4 plum tomatoes, seeded and chopped 2 scallions, minced 1 clove garlic,