Preheat oven to 350°. Combine first 4 ingredients in a greased 2.5-quart baking dish. Top with cheeses. Bake, uncovered, about 1 hour or until casserole is bubbling and cheese is melted. Makes 6-8 servings.
Tip: Substitute 2 cups fresh or frozen vegetables and 1 Tbsp. Onion Onion™ for the stir-fry mixture.