Instructions

1. In a large skillet, brown the sausage over high heat. Remove the sausage from the skillet and drain on paper towels, leaving any rendered fat in the pan.
2. Purée the bell pepper, mushrooms, carrot, and celery in a bullet blender with a few tablespoons of water.
3. Add the puréed mixture to the skillet, season with salt and pepper, and cook until most of the water has evaporated.
4. Add the spaghetti sauce and Parmesan rind to the skillet and simmer for half an hour.
5. Return the sausage to the skillet and simmer for an additional 10 minutes.
6. While the sauce is simmering, cook the spaghetti according to the package instructions.
7. Thin the sauce with pasta water if necessary.