Marinated Chicken Breasts With Grilled Pineapple Relish

Name: Marinated Chicken Breasts With Grilled Pineapple Relish
Ingredients: 1 ripe pineapple, peeled but left whole; 1 jalapeño chile; 1⁄2 red onion; 1⁄2 cup vinegar; 1 tablespoon roasted garlic (see Note); 1 tablespoon salt; 4 boneless, skin-on chicken breasts, 6 to 8 ounces each; 1⁄2 peeled pineapple (remaining from marinade prep); Oil, for coating; Honey, for coating and seasoning, plus 1 tablespoon; Salt, for coating and seasoning; 1⁄2 red onion, peeled and halved; 1⁄4 cup vinegar, plus more to taste; 1⁄2 cup packed cilantro leaves, chopped