To make your honey mustard sauce:

1. In a small bowl, combine your mustard, mayo, honey and a pinch of cayenne pepper.
2. Whisk vigorously until smooth.
3. Set aside until chicken is ready to serve.

To cook your chicken, etc.:

1. Preheat oven to 400 degrees F.
2. In a small bowl, combine olive oil, Dijon mustard, lemon juice, and thyme.
3. Season mixture with salt and pepper, to taste.
4. Brush the mixture onto both sides of each chicken thigh, making sure each piece is well-coated. Allow coated chicken to sit (in the fridge) for 15-20 minutes.
5. When ready to cook, melt butter in a large oven-proof pan/skillet over medium high heat.
6. Once your pan/skillet is sizzling hot, place chicken skin-side down in the pan/skillet, and sear both sides until golden brown, about 2-3 minutes per side. Lift browned chicken out of the pan onto a plate and set aside.
7. Add potatoes to the pan/skillet, and stir to coat each piece with the melted butter/chicken juice mixture in the pan/skillet.
8. Season with salt and pepper, to taste.
9. Place pan/skillet into oven and bake for 18-20 minutes, or until the potatoes are easily pierced with a fork.
10. Pull pan/skillet briefly out of the oven and add asparagus.
11. Stir mixture lightly so that the asparagus and potatoes are evenly distributed in the pan/skillet.
12. Place chicken in the pan/skillet on top of the asparagus and potatoes, then stick the whole thing back in the oven.
13. Roast until the chicken is completely cooked through, about 25-30 minutes.
14. Serve immediately, drizzled generously with your truffle honey mustard sauce.