Preheat oven to 425F. Rinse and dry baby potatoes. Mince garlic cloves.
Zest the lemon and squeeze out lemon juice. In a small mixing bowl whisk together lemon zest, lemon juice, dijon mustard, minced garlic, and olive oil.
Line a baking sheet with parchment paper and arrange the chicken thighs on the baking sheet. Brush the marinade over the top of the bottom of the chicken thighs then flip them over and brush it over the top in a thick layer.
Toss the potatoes in the remaining marinade and place on the baking sheet. Season the chicken thighs and potatoes liberally in salt and fresh cracked black pepper.
Place in the oven and bake at 425F for 35 minutes. Check to make sure the chicken has reached an internal temp of 165F before removing from the oven. Let cool slightly and enjoy!