Cook the pasta according to package instructions. Drain and set aside.
Season the salmon with salt, black pepper, and Italian seasoning.
Heat olive oil in a large skillet over medium heat. Sear the salmon for 3-4 minutes per side until golden brown. Remove from skillet and set aside.
Sauté garlic and red pepper flakes in the same skillet until fragrant.
Make the sauce: Pour in chicken broth and heavy cream, then stir in parmesan cheese and butter. Let it simmer for 2-3 minutes.
Add spinach and let it wilt in the creamy sauce.
Flake the salmon into chunks and return it to the skillet. Stir in lemon juice.
Toss the pasta in the sauce until fully coated.
Garnish with fresh parsley or basil and serve hot!