Preheat & Prep Pan
Preheat oven to 400°F (200°C).
Line a large sheet pan with parchment paper.
Roast Potatoes First
Toss potatoes with 2 tbsp olive oil, garlic powder, salt, and pepper.
Spread on one side of the pan and roast for 15 minutes.
Mix Coating
In a shallow dish, combine panko, Parmesan, garlic powder, Italian seasoning, paprika, salt, and pepper.
Prepare Chicken
Pat chicken dry. Mix olive oil and Dijon mustard, brush onto chicken.
Press each breast into the breadcrumb-Parmesan mixture to coat.
Assemble Sheet Pan
Remove potatoes from oven, push to one side.
Add chicken to the center and broccoli to the remaining space.
Drizzle melted butter over the chicken.
Bake
Roast for 20–25 minutes until chicken reaches 165°F (74°C).
Potatoes should be tender and broccoli slightly charred.
Optional Finish
Broil for 1–2 minutes for extra crispiness.
Rest chicken for 5 minutes before serving.