Heat olive oil in a skillet over medium heat. Season the salmon fillets with salt and black pepper. Cook for 3-4 minutes on each side until golden brown and cooked through. Remove and keep warm.

In the same skillet, melt the butter and sauté the garlic for 1 minute.

Stir in the stock, cream, Dijon mustard, and lemon juice, bringing the sauce to a gentle simmer. Cook for 2-3 minutes until slightly thickened.

Add the fresh tarragon, season with salt and pepper, and stir well.

Return the salmon fillets to the skillet, spoon the sauce over them, and simmer for 1-2 minutes.

Serve immediately with steamed vegetables or rice, garnished with extra tarragon if desired.