Cambodian Grilled Chicken (Mann Oeng K'tem Sor, Marech)

Ingredients:
1 whole chicken (3 1/2 to 4 pounds)
5 cloves garlic, peeled and cut in half
2 tablespoons sugar
1 teaspoon coarse salt (kosher or sea)
1 tablespoon soy sauce
1 tablespoon Asian fish sauce (or more soy sauce)
2 tablespoons vegetable oil
1 clove garlic, peeled and gently crushed with the side of a cleaver
2 teaspoons annatto seeds (achiote), or 2 teaspoons sweet paprika
1 teaspoon coarse salt (kosher or sea)
1 teaspoon freshly ground black pepper
1/2 teaspoon sugar (optional)
2 limes
A grill basket (optional)
1 to 4 hours for marinating the chicken

Instructions:
1. Prepare the chicken and marinade: Remove and discard the fat just inside the neck and body cavities of the chicken. Remove the package of giblets and set it aside for another use. Rinse the chicken, inside and out, under cold running water, then drain and blot it dry, inside and out, with paper towels. Spatchcock the chicken. Make 2 deep slashes to the bone in both sides of the chicken breast and in each leg and thigh. Trim or fold the wing tips back behind the wings. Place the bird in a nonreactive baking dish just large enough to hold it.
2. Place the garlic halves, sugar, and salt in a heavy mortar and pound to a paste with a pestle. Work in the soy sauce and fish sauce. If you do not have a mortar and pestle, combine the garlic, sugar, and salt in a small food processor and puree to a paste, then work in the soy sauce and fish sauce. Spoon the marinade over the chicken, forcing it into the slits and turning the bird to coat it well on both sides. Let the chicken marinate in the refrigerator, covered, for 1 hour to 4 hours; the longer it marinates, the richer the flavor will be.
3. Meanwhile, make the glaze: Heat the oil in a small saucepan over medium heat. Add the crushed clove of garlic and cook until just beginning to brown, about 1 minute. Using a slotted spoon, transfer the garlic to a small heatproof bowl. Add the annatto seeds to the saucepan with the oil and cook until fragrant and browned and the oil turns orange, about 2 minutes. If you are using paprika instead of annatto seeds, cook it for only 15 seconds. Strain the oil through a fine-mesh wire strainer into the bowl with the garlic. Set the glaze aside.
4. Prepare the dipping sauce: Place 1/2 teaspoon each of salt and pepper and 1/4 teaspoon of sugar, if using, in 2 small attractive bowls. Have the limes ready; you'll add the lime juice at the last minute. (See Note.)
5. Set up the grill for direct grilling and preheat it to medium. Leave one section of the grill bare for a safety zone.
6. When ready to cook, brush and oil the grill grate. Drain the chicken and discard the marinade and arrange it on the hot grate or in an oiled grill basket, if using, skin side down. Grill the chicken until it is golden brown and cooked through, 12 to 20 minutes per side. Move the chicken as needed to dodge any flare-ups. Use an instant-read meat thermometer to test for doneness, inserting it into the thickest part of a thigh but not so that it touches a bone. The internal temperature should be about 170°F. Alternatively, you can make a cut in the chicken meat where the thigh connects to the body; there should be no traces of red at the bone. During the last 10 minutes of cooking, start brushing the chicken on both sides with the glaze.
7. To serve, transfer the chicken, skin side up, to a platter. Let it rest for about 2 minutes, then cut it into pieces with a cleaver. Add 2 tablespoons of lime juice to each bowl with the salt, pepper, and sugar for the dipping sauce and stir it with a fork or chopsticks until the salt and sugar dissolves. To eat, dip the pieces of chicken in the salted lime juice.
Khmer Chicken Grilled Using the Indirect Method: You can also grill the chicken using the indirect method, a process that, although not traditionally Khmer, has the advantage of eliminating all risk of flare-ups. Set up the grill for indirect grilling, place a drip pan in the center, and preheat the grill to medium. Place the marinated chicken skin side up in the center of the grate over the drip pan and away from the heat. Cover the grill and cook the chicken until browned and cooked through, 40 minutes to 1 hour. Start brushing the chicken with the glaze during the last 15 minutes of cooking and baste it again every 5 minutes.