Cook the Pasta: Bring a large pot of salted water to a boil and cook the pasta until al dente, following the package instructions. Reserve about 1/2 cup of pasta water before draining.
Cook the Salmon: Season the salmon with the onion powder, salt, and pepper on both sides.
Heat olive oil and butter in a skillet over medium-high heat. Once hot, sear the salmon for 2-3 minutes per side until golden. Transfer to a plate and set aside.
Make the Sauce: Reduce the heat to medium, then add the minced garlic, and cook until fragrant, about 1 minute.
Add the chicken broth, stir in the creme fraiche, capers and lemon juice, whisking until the sauce is smooth.
Add the Parmesan: Whisk the grated Parmesan into the sauce until melted and well combined.
Add the Salmon: Return the salmon to the skillet, breaking it into bite-sized pieces with a fork. Stir gently to coat the salmon in the sauce. Simmer for 3-5 minutes until the sauce thickens slightly.
Combine with Pasta: Add the drained pasta to the skillet. Note: If the sauce is too thick, add the reserved pasta water. Start with 1 tablespoon and gradually add more as needed to adjust the sauce to your desired consistency. Sprinkle in the chopped parsley and toss gently to combine.
Serve with extra Parmesan cheese if desired.