Preheat the oven to 325 degrees F (165 degrees C).

Mix salt and black pepper together, and season chicken first on the meat side. Turn chicken skin side up, pat dry, and season with the rest of the mixture.

Heat oil in an ovenproof pan over high heat. Place thighs in, skin side down, and sear until well browned, without disturbing, about 5 minutes. Turn and sear meat side for 2 minutes. Remove to plate and turn off heat.

Drain or use a paper towel to remove excess fat in the pan, leaving 1 to 2 tablespoons.

Turn heat to medium, add shallots and a pinch of salt, and sauté for a few minutes, just until shallots turn translucent. Add garlic and tomato paste and cook, stirring, for another minute.

Add vinegar and cook, stirring and scraping up browned bits from the bottom of the pan. Add wine and broth, raise heat to high, and bring to a simmer. Add chicken back in, skin side up, and turn off heat.

Bake in the preheated oven until meat is fork tender, 40 to 45 minutes. An instant read thermometer inserted near the center should read about 195 degrees F (90 degrees C).

Remove thighs from pan, and turn heat to high. Boil for a few minutes, or until volume is reduced by half. Add cream and cook until sauce starts to thicken slightly, a few minutes more.

Reduce heat to low and add butter and tarragon. Stir until butter disappears. Add chicken back to the pan, and baste with sauce for a few minutes before serving.