Preheat the oven to 425°F (220°C). Pat the whole chicken dry with paper towels. Rub the outside and inside cavity with 2 tbs olive oil. Season the cavity with 1 tbs kosher salt and 1/2 tsp black pepper. Stuff the cavity with smashed garlic cloves, lemon halves, and rosemary sprigs. Truss the legs with kitchen twine if desired.

Season exterior

Rub the chicken skin with remaining 1 tbs olive oil and sprinkle the outside evenly with the remaining 1 tbs kosher salt and 1/2 tsp black pepper.

Roast

Place the chicken breast-side up on a rack in a roasting pan. Roast in the preheated oven 60–75 minutes, or until the internal temperature in the thickest part of the thigh reaches 165°F (74°C) and juices run clear. Baste once with pan juices halfway through if desired. Remove from oven and tent with foil; let rest 15 minutes before carving. Reserve pan drippings for gravy.

Mashed Potatoes

Boil potatoes

While chicken roasts, place the cut potatoes in a large pot and cover with cold water by 1 inch. Add 1 tsp salt. Bring to a boil over high heat, then reduce to a simmer and cook until potatoes are very tender when pierced with a fork, 15–20 minutes.

Mash

Drain potatoes well and return to the warm pot off heat for 1 minute to help evaporate excess moisture. Mash with a potato masher or ricer. Add 4 tbs butter and warmed 1 cup milk, mashing until smooth and creamy. Season to taste with 1 tsp salt and 1 tsp black pepper. Keep warm until serving.

Roasted Seasonal Vegetables

Prep and roast

Lower oven to 400°F (200°C) after the chicken comes out (you can roast veggies during the last 20–25 minutes of chicken if space and timing allow by using 400°F for both). Toss carrots, broccoli, and red onion with 2 tbs olive oil, 1 tsp salt, and 1 tsp black pepper on a rimmed baking sheet in a single layer. Roast 20–25 minutes, stirring once, until vegetables are tender and caramelized at the edges. Serve hot.

Simple Green Salad

Assemble salad

In a large bowl, combine mixed salad greens, halved cherry tomatoes, and sliced cucumber. Whisk together 2 tbs olive oil, 1 tbs lemon juice or vinegar, and 1 tsp salt; toss with the greens just before serving to avoid wilting.

Gravy (optional)

Make gravy

After removing the chicken, pour reserved pan drippings through a fine mesh strainer into a measuring cup and skim off excess fat if desired, leaving about 1–2 tbs fat. Return 1–2 tbs fat to the roasting pan or a saucepan over medium heat. Whisk in 2 tbs flour and cook 1–2 minutes until lightly browned. Gradually whisk in 1 cup chicken broth and the reserved drippings (or use broth to make 1 cup total liquid). Simmer, whisking, until thickened, 3–5 minutes. Season with 1/2 tsp salt and 1/4 tsp black pepper to taste. Strain again if you want a very smooth gravy.

Carving and Serving

Carve the rested chicken: remove legs and thighs, then breasts and wings. Arrange carved chicken on a large platter with mashed potatoes, roasted vegetables, and salad family-style so adults can serve children. Spoon gravy into a boat or small bowl. Kids 3 and under eat free per the menu offering—portion appropriately and keep child's serving mild (less salt, small pieces).