Crumble sausage into a deep, 3-quart, heat-resistant, non- metallic casserole and add onion.
Heat, uncovered, in Microwave Oven 7 minutes or until sausage is cooked and onion is tender. Stir freequently. Drain off excess fat.
Add cabbage, tomatoes, sugar, oregano, salt and pepper. Stir to combine.
Heat, covered, in Microwave Oven 8 to 10 minutes or until cabbage is tender.
In a small cup mix flour and water until smooth.
Gradually stir flour mixture into sausage mixture.
Heat, uncovered, in Microwave Oven 3 minutes, stirring frequently until thickened.