Step 1

Preheat the oven to 400 degrees. Spread 1/2 cup of marinara sauce over the bottom of a deep pie dish or a rectangular casserole dish. Thinly slice the onion and sprinkle the slices over the marinara.

Step 2

Thinly slice the eggplant, zucchini, yellow squash, and tomatoes (about 1/4 inch thick). The vegetables are easiest to layer when they are the same diameter, so if one of your vegetables is much bigger around than the others, slice the rounds in half or into quarters to make it more similar in size. Layer the vegetables in the casserole dish like dominos. Fit as many of the vegetable slices in as possible.

Step 3

Season the top of the layered vegetables lightly with salt, pepper, dried basil, and oregano. Lastly, add the remaining 1/2 cup of marinara to the top of the vegetables (it doesn't have to be even).

Step 4

Cover the dish with foil and bake for 30 minutes. After 30 minutes, remove the foil and add the shredded cheese to the top. Return the dish to the oven and bake for an additional 10-15 minutes, or until the cheese is melted and lightly browned.