Preheat oven to 350˚F

Season the chicken with kosher salt and pepper on both sides.

Heat the butter and olive oil in a large, deep dutch oven or other pot over medium heat.

Add the chicken to the pot, skin side down, working in batches so as to not crowd the pan.

Cook the chicken until the skin is golden brown and crispy, approximately 7-8 minutes. Flip the chicken and cook on the opposite side until golden.

Transfer to a plate and repeat with the remaining chicken.

Reduce the heat to low and add the onion, carrot and celery. Cook until softened, approximately 4-5 minutes.

Stir in the herbs de Provence and mushrooms cooking until the mushrooms darken.

Add the cornstarch, stirring to coat the vegetables and cooking for 1 minute longer.

Stir in the wine and bring to a boil, scraping the bottom of the pan to release the brown bits.

Add the stock to the pot and bring to a boil.

Transfer the chicken back to the pot, skin side up and pour the juices that have accumulated on the plater into the pot.

Add the bay leaf and cover.

Transfer the pot to the oven and cook for 45 minutes.

Remove from the oven and stir in the half and half, lemon zest and tarragon.

Season with salt and pepper, to taste, if needed.

Serve immediately.