Step 1

Preheat oven to 375F.

Step 2

In a large non-stick skillet add olive oil and sauté onions and garlic 2-3 minutes.  Add 1 tsp salt, black pepper, tomato sauce, red pepper flakes if using, bay leaf, thyme, basil, red and yellow bell pepper; sauté another 5-8 minutes on medium-low heat.

Step 3

In a large nonstick grill pan, grill the zucchini and eggplant 2 to 3 minutes on each side.

Step 4

Add 1 cup of the sauce to a casserole dish.  Layer the eggplant, squash and the zucchini.  Pour the remaining sauce over the top and top with the cheese. Cover with foil and bake 40 minutes.