Pat the chicken thighs dry with paper towels, then season them generously with salt and black pepper. Dry chicken helps create a nice golden sear.

Dice the onion, finely chop the celery, and mince the garlic so everything is ready before you start cooking.

Heat olive oil and butter in a large skillet over medium-high heat. Add the chicken thighs and sear until golden on both sides. Work in batches if needed so the pan isn’t overcrowded.

Transfer the seared chicken to a plate and set it aside while you prepare the sauce.

In the same skillet, add the butter, onion, and celery. Cook for about 5 minutes, stirring occasionally, until softened. Add the garlic and cook for about 1 minute, just until fragrant.

Pour in the white wine and let it simmer until reduced by about half. This step removes the alcohol and concentrates the flavor of the sauce.

Stir in the water or chicken stock, along with the mustard and Dijon mustard, until the sauce is smooth and well combined.

Add the heavy cream, then return the chicken thighs to the skillet along with any juices. Cover and let everything gently simmer for about 10 minutes, until the chicken is tender and cooked through.

Finish with a sprinkle of fresh parsley and serve while hot.