I really have no idea where my Mom got this recipe, I am just thankful she found it. My youngest daughter asks for this for her birthday(or anytime she is home)every year! It makes a ton of spaghetti and is even better the second and third day.
Saute onions and bell pepper in oil. Add beef and cook until browned; drain. Add mushrooms, salt and pepper. Add tomatoes and mix well. Add the spaghetti and cheese. Improves flavor by holding in warm oven.