Sicilian Chicken

This is a recipe my mom started making when I was a teenager, and I've loved it ever since.

4 half boneless skinless chicken breasts
6 Tbsp grated Parmesan cheese (divided)
3 Tbsp flour
2 Tbsp olive oil
1 cup sliced mushrooms
1/2 onion, finely chopped
1/2 tsp rosemary, crushed
1 can Italian Style Stewed Tomatoes

Flatten chicken slightly.  Coat with 4 Tbsp cheese and then flour.  Salt and pepper to taste.  In skillet, cook chicken in oil over medium-high heat until done.  Remove to serving dish; keep warm.  In same skillet, cook mushrooms, onion and rosemary until soft.  Add tomatoes; cook, uncovered, over medium-high heat until thickened.  Spoon over chicken; top with remaining cheese.  Serve over rice.

Note: Chicken can be cooked in microwave, then browned in skillet.