Use culinary scissors to cut the bone out of the thigh. This will ensure even cooking.
Pat the skin side with a paper towel to dry it out. This is essential for getting that crispy texture. Salt both sides and set aside.
In a large cast iron skillet, heat the ghee over medium-high. Make sure it doesn’t smoke.
Once ghee is heated, place the 2 chicken thighs at a time in the skillet, skin side down. Don’t move until the edges turn up slightly and you can tell the skin has browned.
While the skin side cooks, sprinkle garlic powder and tarragon on the meat side.
When the chicken thighs are ready to turn over (about 5 minutes), use tongs to flip and be careful of splatter. This can get messy.
Let cook on the meat side for 5-7 minutes, depending on the thickness.
When cooked though, remove from the skillet and set on a plate to cool. Repeat the above steps with the remaining 2 thighs.
In a small bowl, mix the olive oil, mustard, remaining tarragon, garlic powder and salt. Set aside.
Cut chicken into long strips and drizzle the mustard sauce over the top. Serve immediately.