Rub crock wall with butter. Put zucchini, yellow squash, carrots, mushrooms, broccoli, onions, garlic, seasonings and parmesan in the crockpot. Cover; cook on High 2 hours.
Cook fettucine according to package directions; drain. Add cooked fettucine, mozzarella, cream and egg yolks. Stir to blend well. Allow to heat for 15 to 30 minutes. For serving, turn to Low for up to 30 minutes.
Serves 6.