Instructions:

Cook the pasta:
Bring a large pot of salted water to a boil.
Cook rigatoni according to package instructions until al dente.
Reserve 1/2 cup of pasta water, then drain and set aside.
Cook the salmon:
Season salmon with salt and pepper.
Heat olive oil in a large skillet over medium heat.
Cook salmon 3–4 minutes per side, or until just cooked through.
Remove from skillet and flake into chunks using a fork. Set aside.
Make the sauce:
In the same skillet, melt butter over medium heat.
Add garlic (and shallot, if using) and sauté until fragrant (about 1 minute).
Pour in white wine (or broth), scraping up any browned bits from the pan.
Simmer for 2–3 minutes until slightly reduced.
Add cream and cheese:
Reduce heat to low. Stir in the heavy cream, Parmesan, lemon zest, and red pepper flakes.
Simmer for 3–4 minutes until the sauce thickens slightly.
Combine:
Add the cooked rigatoni and flaked salmon to the sauce.
Toss gently to combine, adding reserved pasta water a little at a time if needed to loosen the sauce.
Stir in lemon juice and fresh parsley. Taste and adjust seasoning.
Serve:
Plate the creamy salmon rigatoni and garnish with extra parsley and Parmesan if desired.