Start by patting the salmon fillets dry with a paper towel. Season both sides with salt, pepper, and garlic powder.
In a large skillet, heat the olive oil over medium-high heat. Once hot, add the salmon fillets, skin-side down. Cook for about 4-5 minutes until the skin is crispy, then flip and cook for an additional 3-4 minutes. Remove the salmon from the skillet and set aside.
In the same skillet, add minced garlic and sauté for about 30 seconds until fragrant. Pour in the chicken broth, scraping the bottom of the skillet to deglaze. Stir in the heavy cream, garlic powder, Italian seasoning, and Parmesan cheese. Mix well and let it simmer for a few minutes until it starts to thicken.
In a small bowl, mix the cornstarch with a tablespoon of water to create a slurry. Slowly whisk this into the sauce, allowing it to thicken to your desired consistency.
Stir in the chopped spinach and sun-dried tomatoes. Cook for an additional 2-3 minutes until the spinach is wilted and everything is heated through.
Return the salmon fillets to the skillet, spooning the creamy sauce over the top. Allow everything to warm together for another minute. Serve immediately, garnished with additional Parmesan cheese if desired.