Pat the salmon fillets dry with a paper towel. Season the salmon on both sides with salt, pepper, paprika, garlic powder and onion powder. Heat the remaining olive oil in a large skillet over medium high heat. Add the salmon and sear it for about 2–3 minutes per side, or until golden and cooked to your liking. Remove the salmon from the skillet and set it aside.
Reduce the heat to medium-low and add the butter to the same skillet. Once the butter has melted, add the spinach and gently stir it until wilted. Add the heavy cream and Boursin cheese. Stir until the cheese has completely melted and the sauce is smooth and creamy.
Taste the sauce and add additional salt and pepper if needed. Return the salmon to the skillet and spoon over the sauce on top. Let everything warm together for another minute or two, then serve warm.