Preheat oven to 350 degrees F.
Brush a 10-inch round cake pan lightly with oil. Cut a piece or parchment paper the same size, place in pan, brush again with oil, and set aside.
Saute onions and garlic in olive oil until soft, then add pepper, mushrooms, and zucchini and continue to cook until soft. Drain off liquid and add oregano, and salt and pepper. Set aside to cool.
In a large mixer bowl, beat eggs, milk, cheddar, Parmesan, and salt and pepper on low speed. When combined, add cream cheese in small bite-sized bits (pull pieces by hand).
Put cooked spaghetti into pan. Do the same with the vegetables. Pour in the egg mixture and mix with your hands so that all the components are equally distributed in the pan. Pat down so that as much of the solids are covered with the liquid.
Bake for 30 to 40 minutes until firm to the touch and lightly brown. It will puff up and settle when cool. Serve immediately. Can serve on a bed of lightly sauteed fresh tomato sauce, if desired.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.