Bring water to a boil in a large sauce pan. Add a generous amount of salt to water. Add pasta, stir down into water and cover. Turn burner off and let pan sit on burner. Pasta will cook while you prepare the sauce.

Sauté onion in olive oil and butter until softened and add zucchini. Cook over medium high heat until zucchini softens and begins to brown. Add corn and cook a few more minutes.

Reduce heat to medium low. Season with salt and pepper. Add 1/4 cup cream and Parmesan. Stir and simmer until cheese melts and sauce forms, adding more cream if needed to reach desired consistency.

Drain pasta, reserving a little of the pasta water*, and add to skillet with vegetables and sauce. Add more cream and cheese if desired. Serve immediately or transfer to a greased casserole dish, cover and refrigerate. Bake refrigerated dish covered at 325 degrees for 30 minutes or until hot. Serves 3-4