1/4 cup (60 milliliters) grated Parmesan, plus more for garnish
Salt and pepper
Heat olive oil in a large pan over medium heat. Add shallot and sauté until soft. Add pieces of sausage and sauté, stirring occasionally.
In the meantime, bring a large pot of salted water to a rolling boil. Add pasta and cook.
As the pasta cooks, combine ricotta cheese and 1/4 cup (60 milliliters) Parmesan in a bowl. Add ricotta mixture to pan with nduja and mix well, turning heat to low. Add a ladleful of pasta water, then season with salt and pepper. When the pasta is al dente, drain, then add pasta to pan and toss to coat in sauce.