Pat salmon fillets dry and season both sides with salt and pepper.
- Heat olive oil or butter in a large skillet over medium-high heat.
- Place salmon fillets skin-side down (if using skin) and cook for 4–5 minutes until crispy and golden. Flip and cook an additional 2–3 minutes until just cooked through. Remove and set aside.
- Reduce heat to medium. In the same pan, add garlic and sauté for 30 seconds until fragrant.
- Add heavy cream, lemon juice, lemon zest, and Dijon mustard (if using). Stir well and simmer for 2–3 minutes until slightly thickened.
- If using, stir in grated Parmesan and mix until melted and smooth.
- Return salmon to the pan and spoon sauce over the fillets. Cook for 1–2 more minutes to heat through.
- Garnish with chopped parsley or dill and serve immediately with your choice of sides.