Preheat the Oven: Preheat your oven to 400°F (200°C). Prepare a large baking sheet by either lining it with parchment paper or lightly coating it with cooking spray.

Prepare the Vegetables: In a large bowl, toss the chopped potatoes, carrots, and red onion wedges with 1 tablespoon of olive oil, 1/4 teaspoon of salt, and 1/4 teaspoon of black pepper. Spread the vegetables evenly on one side of the prepared baking sheet.

Season the Chicken: Pat the chicken breasts dry with paper towels and season both sides with a little salt and pepper. Place the chicken breasts on the other side of the baking sheet, leaving space between each piece.

Make the Honey Mustard Glaze: In a small bowl, whisk together the honey, whole-grain mustard, brown sugar, and 2 tablespoons of olive oil until well combined. Reserve 2 tablespoons of the glaze for later use.

Coat the Chicken: Brush the chicken breasts generously with the honey mustard glaze, making sure to coat both sides.

Roast the Chicken and Vegetables: Place the baking sheet in the preheated oven and roast for 20 minutes.

Add the Broccoli and Asparagus: After 20 minutes, remove the baking sheet from the oven. Add the broccoli florets and asparagus spears to the baking sheet, around the chicken and other vegetables. Drizzle with the remaining 1 tablespoon of olive oil and season with a pinch of salt and pepper. Toss gently to coat the vegetables in the oil.

Finish Roasting: Return the baking sheet to the oven and continue roasting for an additional 10-15 minutes, or until the chicken is cooked through (internal temperature of 165°F or 74°C) and the vegetables are tender and lightly browned.

Glaze and Serve: Remove the baking sheet from the oven and brush the reserved honey mustard glaze over the chicken breasts. Garnish with freshly chopped parsley.

Enjoy: Serve the honey mustard chicken with the roasted vegetables and enjoy this easy, flavorful meal!