In a large oven-safe skillet, heat the olive oil over medium-high heat. Season the salmon fillets with salt and pepper and place them skin-side down in the skillet. Sear for 4-5 minutes until the skin is crispy and the salmon is starting to cook through.
Carefully flip the salmon fillets and cook for an additional 2 minutes. Remove the salmon from the skillet and set aside on a plate.
In the same skillet, lower the heat to medium. Add the minced garlic and sauté for about 1 minute until fragrant, being careful not to burn it.
Pour in the heavy cream, lemon juice, lemon zest, chopped dill, and Dijon mustard. Stir well to combine and let it simmer for 2-3 minutes until slightly thickened.
Add the fresh spinach to the sauce and stir until it wilts. Return the salmon fillets to the skillet, spooning the sauce over them.
Transfer the skillet to the preheated oven and bake for about 10-12 minutes, or until the salmon is cooked to your desired doneness.
Remove the skillet from the oven and let rest for a couple of minutes.
Notes
Serve the salmon on a plate generously drizzled with the creamy sauce, garnished with additional fresh dill and lemon slices on the side for a bright and flavorful presentation.