Pat salmon fillets dry with paper towels. Season both sides with salt and pepper. In a large skillet over medium-high heat, heat olive oil. Sear the salmon for 4–5 minutes per side, until golden brown and cooked through. Remove from the skillet and set aside.

Reduce heat to medium. Add butter and minced garlic to the same skillet. Sauté for about 30 seconds, until fragrant—don’t let it brown.

Pour in the chicken broth, scraping up any browned bits. Stir in the cream, lemon juice, lemon zest, and Dijon mustard (if using). Simmer for 3–4 minutes, stirring occasionally.

Add red pepper flakes (if using), and season with salt and pepper to taste. Let the sauce simmer another 2 minutes, until slightly thickened.

Gently nestle the salmon back into the sauce. Spoon sauce over the fillets and cook for 2–3 more minutes on low heat to let the flavors marry.

Sprinkle with fresh dill or parsley, garnish with lemon slices, and serve hot.