Pat chicken dry and trim any excess fat. Combine salt, pepper, garlic powder, dried thyme, and onion powder. Sprinkle mixture evenly over the chicken, on both sides.
Heat 1 Tbsp of the oil in a large skillet over MED HIGH heat and cook chicken thighs, 3 at a time, for approximately 5-6 minutes per side, or until cooked through.
Transfer chicken to a plate and repeat with the remaining 3 chicken thighs, adding the other 1 Tbsp of oil. Transfer all chicken to plate.
To the same skillet, add butter and heat over MED heat. Add onion and cook 3-4 minutes, until softened, stirring often and scraping the bottom of the skillet with a wooden spoon.
Add garlic and cook about 1 minute more.
Add chicken broth, both mustards, thyme, rosemary, and sage and stir to combine. Stir in heavy cream and bring to a simmer.
Once simmering, reduce heat slightly and continue cooking 3-4 minutes, until sauce has thickened slightly.
Stir in honey and parsley, then return chicken thighs to the skillet. Spoon a bit of sauce over the chicken and serve garnished with additional minced fresh parsley if desired.
