Preheat your oven to 425ºF. Line a rimmed baking sheet with parchment paper and set in the wire rack.
Pat the chicken thighs completely dry, and season both sides with salt + pepper. Place on the wire rack, and roast for 45 minutes, or until crispy + golden brown. Remove and allow to rest for 5 minutes.
While the chicken thighs are resting, make the creamy mustard sauce. In a small bowl or mason jar, combine the chicken stock, dijon mustard and cashew cream. Stir to combine.
Heat a small skillet over medium heat. Melt the ghee, then add the arrowroot starch, whisking constantly until bubbling, about 30 seconds. While whisking constantly, pour in the premixed chicken stock, dijon mustard and cashew cream. Allow to warm and thicken for 1-2 minutes. Season with salt. Add more chicken stock if you want a thinner sauce.
Serve warm with the chicken thighs and creamy mustard sauce. Garnish with fresh thyme. I love these served with my creamy mashed cauliflower and sauteed mushrooms!