Pat the salmon fillets dry and whisk together olive oil, lemon juice, garlic, Dijon mustard, pepper, and salt in a bowl. Marinate for 10-15 minutes.

Heat a skillet over medium-high heat, add olive oil and sear the salmon for 3-4 minutes on each side until golden brown and opaque.

Lower heat, add unsalted butter to the skillet, melt and scrape browned bits from the pan. Add garlic and sauté for 1 minute until fragrant.

Pour in heavy cream, stir to combine, add optional lemon juice, season with pepper and salt, and let it simmer for 2-3 minutes until slightly thickened.

Return the seared salmon to the skillet, spoon creamy sauce over it, and warm through for 1-2 minutes. Stir in parsley before serving.

Plate the salmon with lemon slices for a stunning presentation, best enjoyed immediately.