Prepare the salmon by seasoning both sides with salt, pepper, and garlic powder, then dredge each piece lightly in flour. Heat the olive oil and butter in a skillet over medium-high heat. When the pan is hot, add the salmon and cook for 3-4 minutes on each side until a golden crust forms, being careful not to overcook as the salmon should still be slightly underdone inside. Remove the salmon from the pan and set it aside. In the same skillet, add the chicken broth, lemon juice, and sun-dried tomatoes, allowing the mixture to simmer for a few minutes. Stir in the heavy cream and cook for an additional couple of minutes. Lower the heat to medium-low, then add the spinach and cook until it wilts, about 30 seconds. Return the salmon to the skillet and continue cooking for a few more minutes until the salmon is fully cooked and the sauce has thickened slightly. Serve the dish garnished with fresh basil and grated Parmesan cheese if desired.