Preheat oven to 350 degrees
For the Chicken
Getting a good sear on the chicken is the most important step of this recipe. In a hot pan, drizzle in a small amount of oil. Sear chicken skin side down. Do not turn the chicken until the skin releases with a deep golden sear. Then turn the chicken and cook an additional 2 - 3 minutes on the underside. And don't be afraid of heat. Keep that pan hot over medium high heat.
Transfer chicken, skin side up, to an oven safe safe dish. A 5 quart Dutch oven works wonderful. Toss with chipotle powder, garlic, onion and tomatoes. Add enough chicken broth to cover the the chicken only half-way.
Cover and braise until chicken is cooked to an internal temperate of 165 degrees. About 30 - 45 minutes.
For the Creamy Tequila Sauce:
Reduce the cream. Add cream to a small non-reactive saucepan. Bring to a simmer and Cook for approximately 30 minutes to reduce in volume by half. Do not scrape the bottom of the saucepan with the spoon as scraping the pan dislodges the caramelized whey, altering the color and flavor of the cream.
While the cream is reducing, start preparing the additional ingredients. With a knife, remove the veins and seeds of the chipotle chile peppers. Place the peppers n a small food processor, chop the chipotle chile peppers in adobo into a paste like consistency. Be sure to grab a little bit of the adobo sauce when fishing those peppers out of the can.
In a small saucepan, brown butter over medium high heat. Once the butter has started to turn a golden color, turn down heat, add shallot and cook until tender. Add the chipotle puree and the brown sugar, heating until the sugar is dissolved. Increase the heat to medium high and add tequila and cook for 1-2 minutes for alcohol to evaporate. Whisk in the reduced heavy cream and tarragon and remove from heat. Keep warm.
Remove the braised chicken thighs from the braising liquid to a plate.
To serve, spoon some of the sauce onto individual dinner plates. Add a scoop of rice or polenta and lean the chicken halfway on the polenta and halfway into the sauce.