Bring a large pot of salted water to a boil and cook pasta until al dente according to package directions. Reserve 1/2 cup pasta water, then drain.

While pasta cooks, heat olive oil in a large skillet over medium-high heat. Add sliced smoked sausage and sear until golden and slightly crispy, about 4 minutes. Remove sausage and set aside.

In the same skillet, add chopped onion and a pinch of salt. Sauté until translucent and fragrant, about 3–4 minutes. Stir in garlic and red bell pepper and cook another 1–2 minutes.

Sprinkle in smoked paprika and red pepper flakes; toast briefly to wake up the spices. Pour in chicken broth to deglaze the pan, scraping up any browned bits. Let it simmer for 2 minutes.

Reduce heat to low and stir in the cream. Allow the sauce to thicken gently, about 2–3 minutes. If it becomes too thick, add a splash of reserved pasta water.

Stir in Parmesan (or nutritional yeast) until melted and silky. Return the sausage to the pan and fold in the drained pasta. Toss until everything is coated and glossy — adjust seasoning with salt, pepper, and lemon zest if using.

Serve immediately, sprinkled with chopped parsley or basil and extra Parmesan.