Stems from 2 to 3 bunches kale, collard greens, or Swiss chard
2 tablespoons olive oil, divided
1 medium lemon
2 cloves garlic, minced
3 sprigs plus 1 teaspoon finely chopped fresh rosemary leaves
3 pounds bone-in chicken pieces
1 teaspoon kosher salt, plus more for seasoning
Freshly ground black pepper
Heat the oven to 425°F and arrange a rack in the middle.
Place the stems in a rimmed baking sheet or roasting pan. Drizzle with 1 tablespoon of the oil, season with salt and pepper, and toss to combine. Spread into an even layer.
Finely zest the lemon into a large bowl. Cut the lemon into 8 wedges and set aside. Add the remaining 1 tablespoon of olive oil, garlic, and chopped rosemary to the bowl and stir to combine. Add the chicken and toss with your hands to thoroughly coat. Sprinkle with 1 teaspoon salt and pepper and toss to coat again. Arrange the chicken in an even layer over the stems. Arrange the reserved lemon wedges in between the chicken pieces and place the rosemary sprigs over the chicken.
Roast until the chicken is golden-brown, cooked through, and the thickest piece registers 165°F on an instant-read thermometer, about 30 to 45 minutes. Let the chicken rest for 5 minutes. Serve with the lemon wedges for squeezing over the chicken and greens stems.