Preheat your oven to 425.
Cut the potatoes and carrots into thick chunks and add them to your baking dish. Toss with 2 tablespoons of olive oil, plus salt, pepper, and a sprinkle of garlic powder until well coated.
Truss the whole chicken (tie the legs together with kitchen twine) and gently slide 2 tablespoons of butter under the skin over the breasts. Rub the outside of the chicken with a little olive oil, then season generously with salt, pepper, and garlic powder.
Place the chicken right on top of the vegetables in your baking dish. Roast in a 425°F oven for about 1 ½ hours, or until the thickest part of the thigh reaches 165°F.
Around the 1-hour mark, I loosely cover the chicken with aluminum foil to prevent the skin from getting too dark.
Let the chicken rest for 10–15 minutes before carving, then serve with the roasted veggies and pan juices.