Beat egg and 1 tablespoon milk in a 2-cup cereal bowl until blended. Add sausage. Microwave mixture on high for 30 seconds, then push cooked edges toward the center. Microwave until the egg is almost set, about 15 to 45 seconds longer.
Sprinkle with 1 tablespoon of cheese. Fold omelet in half, slide onto serving plate. Top with remaining cheese. Serve with toasted flatbread, and remaining 8-ounce glass of milk.
410 calories; 16 g fat; 7 g saturated fat; 215 mg cholesterol; 25 g protein; 41 g carbohydrates; 0 g fiber; 650 mg sodium; 451 mg calcium (45% daily value). Nutrition figures based on using lowfat milk in eggs, and include an 8-ounce glass of fat free milk.