Thinly sliced lemons -- whether slipped beneath the skin of a chicken or scattered around it in a pan -- emit an incomparable aroma when roasted, taking on a honeyed overtone without losing any of their sassy edge.

2 russet potatoes peeled and cut into 1/2-inch wedges

Coarse salt, to taste

1 whole chicken (about 6 pounds)

3 garlic cloves, thinly sliced

12 stems of fresh thyme, plus more for garnish

2 lemons, 1 thinly sliced and 1 halved

2 ounces (4 tablespoons) unsalted butter, softened

Freshly ground pepper, to taste

Preheat oven to 375 degrees. Cook potatoes in simmering salted water until just tender, 2 to 3 minutes. Drain.
Place chicken in a roasting pan, breast side up. Scatter potatoes, garlic, 6 thyme stems, and 1/2 of the lemon slices around chicken. Dot potatoes with 1 tablespoon butter divided into small pieces.
Stuff chicken cavity with 1 lemon half and 3 thyme stems. Truss chicken. Rub remaining 3 tablespoons butter on skin.
With your fingers, loosen skin from chicken breasts. Push remaining lemon slices and thyme stems under skin in a single layer. Squeeze juice from remaining lemon half over chicken and potatoes, and season with salt and pepper.
Roast, turning potatoes 2 or 3 times, until a meat thermometer inserted into thickest part of chicken thigh registers 165 degrees, about 1 1/2 hours. Let stand for 15 minutes. Garnish with thyme sprigs.