In a small bowl mix together the flour, salt, and pepper; pour over meat, and stir to coat meat with flour mixture. Stir in the garlic, bay leaf, paprika, Worcestershire sauce, onion, beef broth, potatoes, carrots, and celery.
Cover, and cook on Low setting for 10 to 12 hours, or on High setting for 4 to 6 hours.
Preheat oven to 350 degrees. Grease a cast iron pan with olive oil.
Bring a large pot of lightly salted water to a boil. Cook spaghetti.
Heat a large skillet over medium heat; cook and stir beef and sausage until meat is browned. Stir in spaghetti sauce.
Whisk eggs, Parmesan cheese, and butter in a large bowl. Mix in spaghetti to egg mixture and toss to coat. Place half the spaghetti mixture into cast iron pan. Top with half the mozzarella and meat sauce. Repeat layers. Cover with aluminum foil.
Bake in preheated oven for 40 minutes. Remove foil and continue to bake until the cheese is melted and lightly browned, 20 to 25 minutes longer.
Sprinkle with Italian seasoning, salt, and pepper.