Step 1: Preheat the Oven
Preheat oven to 425°F (220°C).
Line a large sheet pan with parchment paper.
Step 2: Make the Honey Mustard Sauce
In a bowl, whisk together:
Honey, dijon mustard, whole grain mustard, garlic, olive oil, and lemon juice.
Step 3: Season the Chicken
Season chicken with garlic powder, paprika, salt, and pepper.
Brush generously with half of the honey mustard sauce.
Reserve the remaining sauce.
Step 4: Prepare the Vegetables
Toss potatoes, broccoli, carrots, and onion with olive oil, salt, and pepper.
Spread around the chicken on the sheet pan.
Step 5: Bake
Bake for 30–35 minutes until:
Chicken reaches 165°F (74°C)
Vegetables are tender
Potatoes are golden
Step 6: Finish
Brush chicken with the remaining honey mustard sauce.
Bake for another 3–5 minutes.
Step 7: Serve
Sprinkle with parsley and serve immediately.