1 lb. (4 large bunches) red or black seedless grapes
Olive oil cooking spray
Salt and pepper
1 cup (loosely packed) mixed fresh parsley and mint
2 sprigs fresh oregano, leaves stripped (about 2 tbsp.) and chopped
2 lemons—zested (about 1 tbsp.), 1 halved and 1 juiced (about 4 tbsp.)
2 large cloves garlic, finely chopped
4 boneless, skin-on large chicken breasts (about 6 oz. each)
Olive oil, for liberal drizzling
1 cup Greek yogurt
¾ cup toasted walnuts
½ cup crumbled feta
Preheat the oven to 400°. Place the grapes on a rimmed baking sheet. Spray with the cooking spray; season with salt and pepper. Roast until the grapes just begin to burst, about 15 minutes.
Heat a large cast-iron skillet over medium-high. Wrap 2 bricks with foil. (If you don’t have any bricks, you can use a large heavy skillet, instead.)
Finely chop the parsley and mint and place about 1/4 cup in a food processor. In a small bowl, mix the remaining chopped parsley and mint with the oregano, lemon zest and garlic. Using your fingers, loosen the skin of the chicken breasts and stuff the herb mixture under the skin. Coat the chicken with the olive oil and season liberally on both sides. Place the chicken, skin side down, in the skillet and top with the bricks. Cook until the skin is browned and very crisp, 7 to 8 minutes. Transfer the skillet to the oven and roast until the chicken is cooked through, 5 to 8 minutes. Remove the bricks. Transfer the chicken to a platter and place the halved lemon in the pan, cut side down. Let the lemon cook until browned by the carry-over heat of the skillet, about 2 minutes. Squeeze the lemon over the chicken.
In a food processor, puree the yogurt, walnuts, feta and lemon juice into a smooth, thick sauce; season. Slather a swirl of the sauce on each plate. Slice the chicken breasts and fan 1 breast on each plate over the yogurt sauce. Serve with the roasted grapes.