Prepare the Chicken: Season the chicken thighs generously with salt and freshly ground black pepper.​

Sear the Chicken: In a large Dutch oven or heavy-bottomed pot, melt the unsalted butter over medium-high heat. Add the seasoned chicken thighs, skin side down, and cook until the skin is golden brown, about 5-7 minutes. Flip and brown the other side for an additional 5 minutes. Remove the chicken from the pot and set aside.​

Sauté Vegetables: In the same pot, add the diced shallots and celery. Sauté until softened, approximately 3-4 minutes. Add the halved mushrooms and cook until they release their moisture and begin to brown, about 5 minutes. Stir in the minced garlic and cook for another minute until fragrant.​

Create the Roux: Sprinkle the all-purpose flour over the sautéed vegetables, stirring constantly to form a roux. Cook for 2 minutes to eliminate the raw flour taste.​

Deglaze and Simmer: Pour in the dry white wine, scraping up any browned bits from the bottom of the pot. Allow the wine to reduce by half, then add the chicken stock, stirring to combine. Bring the mixture to a simmer.​

Add Potatoes and Herbs: Introduce the halved baby potatoes, fresh thyme sprigs, rosemary sprig, and bay leaf to the pot. Nestle the browned chicken thighs back into the mixture, ensuring they are partially submerged in the liquid.​

Braise: Cover the pot, reduce the heat to low, and let it simmer gently for 30 minutes, or until the chicken is cooked through and the potatoes are tender.​

Finish with Cream: Stir in the heavy cream, allowing the sauce to meld and thicken slightly. Simmer uncovered for an additional 5 minutes.​

Serve: Remove the bay leaf and herb sprigs. Adjust seasoning with salt and pepper to taste. Serve the casserole hot, garnished with additional fresh herbs if desired.