Heat the olive oil in a medium frying pan over medium heat. Add the sausage and cook until browned, around 5-7 minutes. Place a paper towel on a plate. Remove the sausage from the pan and place on the paper towel to cool. Set aside.
Return the pan to the stove and add the onion and carrots. Cook over medium heat until the carrots soften, around 10-15 minutes. Add 2 tablespoons of butter and melt. Add the mushrooms and cook an additional 10-15 minutes until the mushrooms have softened. Add the garlic and continue cooking an additional minute until fragrant.
Add the beef stock, tomatoes, sage, rosemary, salt and pepper. Bring to a boil and then turn the heat down to medium low and simmer for one hour.
20 minutes before the sauce is done, start boiling water in a large pot for the rigatoni. Boil the rigatoni until al dente and drain. Set aside.
When the sauce is done remove the rosemary and sage sprigs. Pour the sauce over the rigatoni to combine. In a casserole dish add the rigatoni. Place the burrata cheese on top of the rigatoni. Bake for 12-15 minutes until the cheese has melted. Serve hot and enjoy!