Begin by browning the sausage thoroughly in a pot, allowing it to develop a rich color before taking it out. The browned bits left in the pot will form the base of your sauce.

Next, cook the mirepoix longer than you might expect. Since the vegetables are finely chopped, they will release a lot of moisture. Continue cooking until this moisture evaporates, and the mixture becomes soft, concentrated, and lightly golden.

Caramelize the tomato paste by letting it cook for 2 to 3 minutes in the pot before adding any liquid. It should turn a deep brick red color to enhance the flavor.

Consider adding marinara sauce for extra flavor. In the future, you might try substituting 1 cup of chicken broth with 1 cup of marinara for a richer tomato taste and a saucier dish.

Keep some extra liquid on hand, as one-pot pasta tends to absorb liquid quickly. Add hot broth or water in small amounts whenever the mixture starts to thicken.

When you finish cooking, the pasta should appear slightly looser than you want it to be when you turn off the heat.

For a silkier sauce, you can stir in a tablespoon or two of butter, or for a richer texture, add a small splash of cream. While these additions are optional, they can enhance the dish.

Finally, don't forget to add a touch of acidity. A teaspoon of sherry vinegar or lemon juice will brighten the flavors of the sausage, beans, tomato, and Parmesan without making the pasta taste sour.