Preheat oven to 400ºF. On one half of the baking sheet, combine the quartered baby red potatoes and the cherry tomatoes. On the other half of the baking sheet, arrange the sliced mushrooms, avoiding overlap as much as possible. Drizzle the vegetables with the oil and season with salt and pepper. Arrange the thyme sprigs and sage leaves on top. Set the baking sheet aside as you fry the chicken.

In a wide sauté pan or braising pot, heat the neutral cooking oil over medium-high heat. Pat the chicken dry and season all over with salt and pepper. Once the oil is hot, place the chicken, skin-side down, into the pan. Cook without moving for 5-7 minutes or until the skin is crispy and golden brown. Flip and cook 1-2 minutes more. Transfer to a plate.

Keeping the pan on medium heat, add the diced onion and cook for 4-5 minutes or until it just begins to soften. Add the crushed garlic, thyme sprigs, chopped tarragon, and torn sage leaves and cook for 2-3 minutes more.

Pour in the chicken stock and scrape up any browned bits stuck to the bottom. Bring to a boil and then turn off the heat.

Place the chicken on top, skin-side up. Transfer the pan to the oven and immediately add the baking sheet of vegetables to the unused rack in the oven. Bake for 30-40 minutes or until the chicken reaches 165ºF on an instant-read thermometer.

After baking, remove the vegetables from the oven and keep warm. Return the chicken to the stove top. Transfer the chicken to a plate and cover with foil.

Pour the sauce through a sieve into a saucepan.

Transfer the saucepan to the stove over medium-high heat. Bring to a boil and boil for 5 minutes until reduced slightly.

Add the butter and reduce heat. Pour in the heavy cream and simmer for 5 minutes more until thickened slightly. Taste and season with salt and pepper.

Divide the roasted vegetables between rimmed plates or shallow bowls. Place a chicken leg on top of each each dish and spoon the creamy tarragon sauce over each plate. Arrange a few tarragon leaves on top of the chicken for garnish. Enjoy!