Pat the salmon dry with a paper towel. Season with salt and pepper. Heat the olive oil in a frying pan and sear the salmon over medium-high heat until golden and the skin side is crispy, approximately 6-7 minutes. Remove the salmon to a plate until later.

In the same pan, add the butter and diced shallot. Sauté over low heat for 5 minutes, then add minced garlic and sauté for 30 seconds. Deglaze the pan with white wine and let it simmer for about 3-5 minutes until reduced by half.

Add chicken stock, heavy cream, and grated Parmesan cheese. Stir until the cheese is incorporated, then add the asparagus and cook for 5 minutes.

Return the salmon to the pan, add spinach, and cover. Let the sauce simmer over low heat for 5 minutes or until the salmon is cooked through and spinach is wilted. Season with salt to taste.