Heat the oven. Preheat to 425°F (220°C). Line a large rimmed sheet pan with parchment or lightly oil it. High heat helps veggies caramelize and keeps chicken juicy.

Make the lemon garlic mixture. In a bowl, whisk lemon zest, lemon juice (about 3–4 tablespoons), minced garlic, 2 tablespoons olive oil, Dijon, honey, oregano, paprika, red pepper flakes, 1 teaspoon salt, and 1/2 teaspoon black pepper. This is your marinade and pan sauce base.

Season the chicken. Pat chicken dry. Add to half of the lemon mixture and toss to coat. Let it sit while you prep the vegetables, 10–15 minutes. Tip: Thighs are forgiving; if using breasts, pound to even thickness for consistent cooking.

Prep the veggies. In a large bowl, toss potatoes, broccoli, bell pepper, and red onion with remaining 1 tablespoon olive oil and the other half of the lemon mixture. Season with a pinch more salt and pepper.

Arrange on the pan. Spread the vegetables on the prepared sheet pan in an even layer. Nestle the chicken pieces among the veggies, leaving space so everything can roast, not steam.

Roast. Bake for 20 minutes. Check for browning and give the pan a gentle toss, flipping the chicken if needed. Continue roasting 5–10 more minutes, until the chicken reaches 165°F (74°C) in the thickest part and the potatoes are tender.

Optional broil for color. If you like extra charring, broil for 1–2 minutes at the end, watching closely.

Rest and garnish. Let the pan rest 5 minutes so juices redistribute. Sprinkle with chopped parsley. Taste and finish with a squeeze of lemon or a pinch of salt if needed.

Serve. Plate the chicken with a big scoop of veggies and spoon over any pan juices. Great with a side of crusty bread, rice, or quinoa to catch the sauce.