Pat dry chicken thighs with paper towels and season generously with salt and pepper. Set aside.

Preheat your oven to 190°C (375°F).

Finely chop shallots and garlic and set aside in separate bowls.

Gather liquids: mix white wine or stock with vinegar, and measure chicken stock, crème fraîche, and Dijon mustard.

In a large oven-safe skillet, heat olive oil and unsalted butter over medium-high heat.

Sear chicken thighs skin-side down for about 7-9 minutes until golden brown, then flip and cook for 3-4 minutes more.

Transfer seared chicken to a plate and let rest while preparing the sauce.

Sauté shallots in the same skillet for about 4-5 minutes until translucent.

Add minced garlic and cook for 30-60 seconds until fragrant.

Deglaze the skillet with prepared liquid mixture, scraping up any flavorful bits, and let simmer for 2-3 minutes.

Whisk in chicken stock and mustard, simmer until sauce thickens slightly, about 5 minutes.

Stir in crème fraîche, thyme, and tarragon if using, and adjust seasoning as needed.

Return chicken thighs to the skillet, skin-side up, and surround with creamy sauce.

Transfer skillet to the preheated oven and bake for 20-25 minutes until chicken reaches 74°C (165°F).

Remove from oven and tent chicken with foil for 5-10 minutes before serving.

Garnish with parsley and serve alongside creamy mashed potatoes or salad.