Place all ingredients except spaghetti, parmesan, water and cornstarch into crock pot; stir.
Cook on low for 6-8 hours.
Serve over cooked spaghetti; sprinkle with parmesan cheese.
Prior to serving, you'll probably want to thicken this a little more. Mix lukewarm water and cornstarch in a bowl until corn starch is dissolved. Add to crock pot mixture. Stir until thickened. If it it not thick enough you may repeat this step.