PREHEAT oven to 350°F. Heat oil in medium skillet on medium-high heat. Add mushrooms; cook 4 min. or until tender, stirring occasionally. Set aside. Beat eggs, milk and mayo in large bowl with wire whisk until well blended. Stir in stuffing mix.
SPOON stuffing mixture into greased 9-inch square baking dish; top with mushrooms, tomatoes and onions.
BAKE 35 min.; sprinkle with cheese. Bake an additional 15 min. or until cheese is melted and center is set. Let stand 10 min. before serving.
KRAFT KITCHENS TIPS
Healthy Living
Save 70 calories and 8 grams of fat per serving by preparing with KRAFT Mayo Light Mayonnaise and KRAFT 2% Milk Shredded Reduced Fat Cheddar Cheese, and substituting 1-1/2 cups cholesterol-free egg product for the 6 eggs.
Make Ahead
Cover unbaked casserole tightly with plastic wrap; freeze until solid. Cover with foil. Freeze up to 3 months. When ready to serve, preheat oven to 350°F. Remove foil and plastic wrap. Discard plastic wrap. Re-cover casserole with foil. Bake 1 hour. Remove foil; sprinkle casserole with cheese. Bake, uncovered, an additional 15 min. or until center is set and cheese is melted. Let stand 10 min. before serving. To decrease the baking time, thaw casserole in refrigerator overnight, then bake, uncovered, 40 min. or until center is set and cheese is melted.
RECIPE COURTESY OF KRAFT FOODS