Preparation

• Preheat oven to 350 degrees
  Tomato beef sauce:
  In Dutch oven, heat oil. Cook onion, garlic, oregano, basil, and thyme, for about 4 min. Add beef. Cook breaking up with spoon until no longer pink. Add mushrooms, carrots, zucchini, and pepper. Cook stirring often until liquid is evaporated. Remove from heat. Stir in cheese and vinegar.
  
  Cheese sauce:
  In saucepan, melt butter. Whisk in flour, stirring for 1 minute. Add milk; whisk until sauce boils and thickens. Transfer to bowl; let cool 10 minutes. Blend in ricotta, egg and cheese.
  Cook spaghetti for 5 minutes or until almost tender but still firm. Drain and toss with beef sauce.
  
  Spread in a baking dish (13x9-inch). Spoon cheese sauce over. Sprinkle with Parmesan cheese. Bake for 40 minutes.