Combine egg and 1 tablespoon milk in 2-cup cereal bowl until blended. Add sausage. Microwave on high for 30 seconds; push cooked edges toward center. Microwave until the egg is almost set, about 15 to 45 seconds longer. Top with cheese.
Place on flatbread and fold. Cut out center of sandwich, using a 2 to 2-1/2-inch cookie cutter. Cut the remaining sandwich into 4 or 5 pieces. Serve with remaining 8-ounce glass of milk.
400 calories; 18 g fat; 7 g saturated fat; 215 mg cholesterol; 26 g protein; 34 g carbohydrates; 1 g fiber; 700 mg sodium; 471 mg calcium (45% daily value). Nutrition figures based on using lowfat milk in eggs, and include an 8-ounce glass of fat free milk.