Step 1

Heat oven to 350°F.

Step 2

Cook and stir first 5 ingredients in large skillet on medium-high heat 6 to 8 min. or until vegetables are crisp-tender and lightly browned.

Step 3

Add tomatoes; cook 15 min., stirring occasionally. Spoon into casserole; top with grated topping and mozzarella.

Step 4

Bake 15 min. or until mozzarella is melted and vegetable mixture is heated through.