Step 1

To prepare chicken: Heat oil, garlic halves, lemongrass and ginger in a medium skillet over medium heat. Cook, stirring, until starting to brown, about 2 minutes. Immediately transfer the mixture to a large bowl and add water, 1 cup tamari and orange. Add chicken, cover and refrigerate for at least 6 hours and up to 1 day.

Step 2

Meanwhile, to prepare sauce: Puree pineapple juice and pineapple in a blender until smooth. Transfer to a medium saucepan and add tamari, brown sugar, garlic, scallion, ginger, shallot and vinegar. Bring to a boil over medium-high heat; cook, stirring occasionally, until reduced by half, 8 to 10 minutes.

Step 3

Position rack in upper third of oven; preheat to 425 degrees F. Line a rimmed baking sheet with foil.

Step 4

Remove the chicken from the marinade and pat dry with paper towels. (Discard the marinade.) Place on the prepared pan. Bake until an instead-read thermometer inserted in the thickest part without touching bone registers 160 degrees F, about 25 minutes. Brush with 2 tablespoons of the sauce. Increase oven temperature to broil. Broil on high until charred in spots, 2 to 3 minutes.