Lemons used every which way (juiced, zested, sliced, squeezed, and baked inside the chicken) give this classic dish a fresh new spin.
Preheat the oven to 400°. In a large bowl, toss the squash, 1 tbsp. oil, and 1 1/2 tsp. chopped rosemary. Season the squash with salt and pepper.
Juice 1 lemon. (You should have about 1/4 cup.) In a bowl, mix the lemon juice, remaining 1/4 cup oil, remaining 1 tbsp. chopped rosemary, and the wine to make the basting sauce.
Using a vegetable peeler, remove the zest from 1 lemon. Using a fork, pierce the lemon in several places. Season the chicken with salt and pepper, then rub with about 1 tbsp. of the basting sauce. Insert the peeled lemon into the cavity. Using kitchen twine, loosely tie the legs together.
Slice 1 lemon. On a rimmed baking sheet, spread the squash out in an even layer, leaving room for the chicken in the center. Place the chicken directly on the baking sheet in the center. Tuck a few lemon slices around the chicken. Place the rosemary sprig on top.
Roast, basting the chicken occasionally with the sauce, until the squash is tender and charred in spots and an instant- read thermometer registers 165° when inserted into the thickest part of the thigh (do not touch the bone), about 1 hour.
Transfer the chicken and squash to a platter. Cut the remaining lemon in half and squeeze over the chicken.