Heat The Oven And Prep The Pan Preheat your oven to 425°F. Line a large rimmed sheet pan (around 18×13 inches) with parchment or foil. If you own a wire rack that fits inside, you can put it under the chicken area for extra crisp bottoms, but it’s optional. This little bit of prep makes everything easier later—especially cleanup.

Give The Potatoes A Head Start In a bowl, toss the chopped potatoes with: 1½–2 Tbsp olive oil Half of the minced garlic 1–2 Tbsp grated Parmesan A pinch of salt and pepper Spread the potatoes over about one-third to half of the pan in a single layer. Bake for 10–15 minutes, until they just start to brown at the edges. Potatoes take longer than chicken and green beans, so this head start keeps everything done at the same time. Think of it as staggering the cast so they hit the stage at the perfect moment.

Mix The Parmesan Crust In one shallow bowl, mix the wet mixture: Melted butter, olive oil (if using), lemon juice, a pinch of salt and pepper. In another shallow bowl, mix the dry coating: Parmesan, Panko, Italian seasoning, garlic powder, onion powder, smoked paprika, salt, pepper. Stir until everything looks evenly combined and colorful. You want the crumbs to look well seasoned—if it looks a little plain, add another pinch of paprika or herbs.

Prep And Coat The Chicken Pat the chicken dry with paper towels so the coating sticks better. Season both sides lightly with salt and pepper. Working one piece at a time: Dip the chicken into the wet mixture, letting extra drip off. Press it firmly into the Parmesan–Panko mix, coating both sides. For extra crunch, you can do a quick double dip: wet → crumbs → wet → crumbs again. If crumbs fall off a bit, that’s normal. Just press more on top once they’re on the pan.

Add Chicken And Prep The Veggies Pull the pan with potatoes from the oven. Push the potatoes to one side. Lay the coated chicken pieces in the center of the pan, leaving a little space between them. In the same bowl you used for potatoes (no need to wash): Toss green beans with 1–2 Tbsp olive oil, the rest of the garlic, a pinch of salt and pepper, and 1–2 Tbsp Parmesan if you like. Spread the green beans on the remaining third of the pan in a single layer. You now have a full pan: potatoes, Parmesan crusted chicken, and veggies all sharing the same hot real estate.

Roast Everything Together Return the sheet pan to the oven. Bake for 20–25 minutes, until: Chicken reaches 165°F in the thickest part (use an instant-read thermometer if you have one). Potatoes are tender and golden. Veggies are bright and tender-crisp with some browned spots. If your chicken pieces are on the thinner side, start checking around 18–20 minutes.

Broil For Extra Crunch (optional but lovely) If you’d like deeper color and crispier topping: Switch the oven to broil for 2–4 minutes. Keep the pan on the middle rack and watch closely so the topping doesn’t burn. That last blast of heat is like turning up the volume on the Parmesan crust.

Rest, Garnish, And Serve Let the chicken rest on the pan for 5 minutes. This helps the juices settle and the crust firm up. Sprinkle chopped parsley over the top. Add lemon wedges to the pan or the plate and a bit more grated Parmesan if you’re feeling generous. That’s it—one pan, full dinner, very few dishes in the sink.