Brown the meat. Heat 1 Tbsp olive oil in a Dutch oven or large soup pot over medium-high heat. When hot, add ground meat then cook, stirring occasionally, until browned on all sides, about 4-5 minutes. If wanted, drain off excess grease from beef or sausage.
Sauté onion. Add chopped onion, then season with ½ tsp Kosher salt. Cook, stirring occasionally, until softened, about 2-3 minutes, then add 3 chopped garlic cloves. Cook 1 minute more. Stir in 2 tsp dried oregano and ¼ tsp crushed red pepper flakes.
Add liquid. Add 3 Tbsp tomato paste, then use a spatula to break it up until it dissolves. Add 1 (28oz) can crushed tomatoes, 6 cups low-sodium chicken broth, and 1 bay leaf. Stir in fresh basil leaves and Parmesan rind, if using. Bring to a boil, then reduce heat to a simmer.
Add noodles. Stir in 8oz pasta noodles, then cook for 12-15 minutes, or until the pasta is cooked to your liking. Meanwhile, make the ricotta cheese topping.
Make the ricotta cheese mixture. In a medium bowl, mix together 1 cup ricotta cheese, ½ cup grated Parmesan, remaining ½ tsp Kosher salt, and ¼ tsp black pepper. Set aside
Finish the soup, then broil with cheese. Remove the bay leaf and Parmesan rind. Stir in ¼ cup heavy cream and 1 cup shredded mozzarella cheese to the soup until melted. Taste, adjust seasoning as needed, then spoon into serving bowls. Place individual portions of soup on a rimmed baking sheet, then dollop each with some of the ricotta cheese mixture. Place under a broiler set to high for 1-2 minutes (keeping a close eye on it so it doesn’t burn), just until the cheese melts and turns golden brown and bubbly. Sprinkle with chopped parsley or fresh basil leaves, then serve immediately with extra black pepper.