Heat the oven: Preheat to 400°F (205°C). Lightly grease a 9x13-inch baking dish or line it with parchment for easy cleanup.
Make the sauce: In a bowl, whisk together honey, Dijon, whole-grain mustard (if using), vinegar or lemon juice, garlic, oil, smoked paprika, salt, and pepper until smooth.
Arrange the chicken: Pat the chicken dry and place it in the baking dish in a single layer. Sprinkle with a pinch of salt for good measure.
Dump and coat: Pour the honey mustard sauce over the chicken and turn pieces to coat.
If using herbs, scatter them over the top.
Bake: Cook for 20–25 minutes for breasts, or 25–30 minutes for thighs, until the internal temperature reaches 165°F (74°C).
Broil for caramelization: Optional but recommended. Broil for 2–3 minutes to thicken and brown the glaze. Watch closely to avoid burning.
Rest and serve: Let the chicken sit for 5 minutes so the juices settle.
Spoon extra sauce from the pan over each piece.