Trim excess fat off chicken thighs
Pat dry and season with salt and pepper on both sides
Heat oil in a traditional 12" skillet (used to create fond or browning for sauce)
Place thighs in skin side down and turn when browned
Brown the other side and then remove to plate
Turn down heat and add shallots and garlic
Cook until softened
Add chicken stock, wine and vinegar
Stir and lift fond off of pan
When simmering add thighs back to pan
Put into 325F oven for about 30 minutes until thighs reach 195F
Remove thighs to plate and tent to keep warm
Reduce sauce to 1 1/4 cups
Take off heat, add butter and tarragon
Whisk into sauce and add 1 tsp vinegar
Pour sauce onto plate with thighs and serve