Step 1: In a large Dutch oven or heavy pot, heat olive oil over medium-high heat. Add the ground beef and Italian sausage, breaking it apart with a wooden spoon. Cook until thoroughly browned.
Step 2: Use a slotted spoon to remove the meat from the pot and set aside. Drain all but 2 tablespoons of the rendered fat.
Step 3: Add the onion, carrots, and celery to the pot. Sauté for 6-8 minutes until softened. Add the minced garlic and tomato paste, cooking for another 2 minutes until fragrant.
Step 4: Return the browned meat to the pot. Stir in the crushed tomatoes, tomato sauce, beef broth (or wine), oregano, basil, sugar, salt, and pepper.
Step 5: Bring the mixture to a gentle boil, then reduce heat to low. Cover partially and simmer for at least 45 minutes to 1 hour, stirring occasionally to prevent sticking.
Step 6: Taste and adjust seasonings if necessary. Serve hot over your favorite pasta and garnish with fresh parsley or parmesan cheese.