Ingredients

• 3 tablespoons extra-virgin olive oil

• 1 medium-size white onion, thinly sliced (about 2 cups)

• 2 cups large seedless red grapes, divided

• 2 small leeks (white and light green parts only), thinly sliced (about 1 cup)

• 6 medium garlic cloves, sliced (about 2 1/2 tablespoons)

• 1 teaspoon kosher salt, plus more to taste

• 1 to 2 tablespoons water, as needed

• 2 tablespoons balsamic vinegar, plus more to taste

• 1 (750-milliliter) bottle Lambrusco

• 1 3/4 cups chicken broth

• 1 (750-milliliter) bottle dry red wine

• 1 1/4 cups packed light brown sugar

• 3/4 cup (6 ounces) Lambrusco

• 3/4 cup red wine vinegar

• 1 medium-size sweet onion, thinly sliced

• 1 1/2 teaspoons fresh lemon juice, plus more to taste

• 1 teaspoon toasted black peppercorns

• 1/2 teaspoon kosher salt, plus more to taste

• 4 cloves garlic

• 1 thyme sprig

• 1 rosemary sprig

• 1 bay leaf

• 1 (3 1/2-lb.) whole chicken

• 4 teaspoons kosher salt

• 1/2 teaspoon black pepper

• 1 medium-size sweet onion, cut into 3/4-inch-thick slices

• 5 medium garlic cloves, crushed

• 2 thyme sprigs

• 2 rosemary sprigs

• Sliced red grapes, chopped fresh chives, fresh rosemary leaves, ground black pepper, and flaky sea salt, for garnish