Preheat the oven to 375°.
In a small size bowl whisk together the ricotta, egg, spinach, salt and pepper until combined. Set aside.
Add a small amount of Rao’s Homemade® Four Cheese Sauce to the bottom of a 12 x 8 casserole dish and spread it around.
Next, add a layer of thinly sliced green zucchini covering the tomato sauce.
Spread a small amount of the ricotta mixture onto each zucchini slice. Sprinkle with a small amount of mozzarella.
Next, drizzle on a small amount of the Four Cheese sauce. Repeat the exact same process with the yellow squash and then again with the eggplant and then create those same layers 2 more times topping off with the remaining ricotta mixture, 4-cheese sauce, mozzarella and parmesan cheese.
Bake in the oven at 375° for 45 minutes or until the cheese is melted and browned.
Remove from the oven, slice and serve.