Melt margarine in large skillet on medium-high heat. Add onions; cook and stir 3 min. Add mushrooms, carrots and garlic; cook and stir 6 min. or until carrots are crisp-tender. Add flour; cook and stir 2 min. Gradually stir in milk. Bring to boil, stirring frequently. Remove from heat. Stir in spinach, 1 cup Mozza-Cheddar and Parmesan.