Spray a 13x9 baking dish with olive oil and set aside. Prepare your polenta by boiling 6 cups of water, then slowly adding in the corn grits, stirring consistently to avoid lumping. Reduce heat and let simmer on low heat for approximately 30 minutes. Keep stirring mixture while it is cooking. 5 minutes before polenta is done, add in olive oil and Italian seasonings. Remove from heat and evenly spread the polenta into the greased baking dish. Let it sit to mold, approximately 15 minutes.

In the meantime, saute the onions and garlic until fragrant. Add salt and pepper to taste. Add yellow squash, zucchini, mushrooms and spinach. Saute until fully cooked. Top the polenta with the cooked vegetables, making sure to strain the liquid from the pan to avoid creating a mushy dish. Slowly pour the red sauce over the vegetables and top with parmesean cheese. Bake on center rack until cheese is melted, approximately 10-15 minutes.