Layered Vegetable Bake

1 pkg. (6 oz.) Stuffing Mix for Chicken
5 eggs, divided
1-1/2 cups Shredded Cheddar & Monterey Jack Cheese, divided
1 medium onion, chopped
1 pkg. (10 oz.) frozen chopped spinach, thawed, drained
1/2 of a small red pepper, cut into strips
2 medium tomatoes, sliced

PREHEAT oven to 400°F. Prepare stuffing mix as directed on package. Add 1 of the eggs; mix until well blended. Press firmly onto bottom of greased 9-inch square baking dish; sprinkle with 3/4 cup of the cheese. Set aside.
SPRAY medium nonstick skillet with cooking spray. Add onions; cook and stir 5 min. or until tender. Remove from heat; stir in spinach. Spoon half of the spinach mixture over cheese layer in baking dish; top evenly with peppers. Cover with layers of the remaining 3/4 cup cheese and remaining spinach mixture. Beat remaining 4 eggs lightly; pour over ingredients in baking dish. Top evenly with tomatoes.
BAKE 40 to 45 min. or until center is set.