Pat the salmon fillets dry with paper towels, then season both sides generously with salt and pepper.

Heat the olive oil in a large skillet over medium-high heat. Carefully place the salmon in the pan, skin-side down, and cook for 4 minutes. Flip and cook for another 4 minutes, until golden and cooked through. Remove the salmon to a plate and set aside. Pour off any excess oil from the pan.

Reduce the heat to medium and add the butter to the skillet. Once melted, add the minced garlic and chopped sun-dried tomatoes. Cook, stirring, for 1 to 2 minutes until fragrant.

Pour in the chicken stock and let it simmer for 1 minute. Slowly stir in the heavy cream, then add the cayenne pepper and dried basil. Bring to a gentle boil for 1 to 2 minutes, stirring occasionally.

Add the spinach to the sauce and stir until it wilts, about 30 seconds. Taste the sauce and adjust seasoning with salt and pepper as needed. If the sauce seems too thin, whisk together 1 teaspoon of cornstarch with 2 tablespoons of water and stir it in; if too thick, add a splash more chicken stock.

Return the salmon fillets to the skillet, spooning the sauce over them. Let everything simmer together for 1 minute. Remove from heat and serve immediately over pasta, rice, or with crusty bread.