Pollo Yucateco Asado (Yucatán-Style Grilled Chicken)

Toast oregano, cumin seeds, clove, and allspice in a small skillet over medium until fragrant, about 2 minutes. Pulverize toasted spices using a molcajete or a spice grinder until finely ground. Juice 2 oranges to yield 1/3 cup juice. Cut remaining orange crosswise into 1/4-inch-thick slices; set orange slices aside.

Whisk together ground toasted spices, reserved 1/3 cup orange juice, vinegar, achiote powder, oil, salt, white pepper, and garlic powder in a medium bowl until well combined. Combine chicken, orange slices, and vinegar-spice mixture in a large ziplock bag. Seal bag; shake to mix, and gently massage marinade into chicken. Chill at least 2 hours or preferably overnight (up to 12 hours).

Remove ziplock bag from refrigerator, and let stand at room temperature while grill preheats. Preheat one side of a gas grill to high (450°F to 500°F), or push hot coals to one side of a charcoal grill.

Remove chicken and orange slices from marinade, letting excess marinade drip off. Set orange slices aside. Discard marinade. Place chicken thighs, skin side down, on lightly oiled grates over lit side of grill. Grill, covered, until skin develops grill marks, about 3 minutes. Flip chicken, and grill, covered, until chicken is lightly charred, about 3 minutes. Transfer chicken to unlit side of grill, and grill, covered, flipping occasionally, until a thermometer inserted in thickest portion of chicken registers 165°F, 15 to 20 minutes. Transfer chicken to a platter, and let rest 5 minutes.

While chicken rests, place orange slices on oiled grates over lit side of grill. Grill, uncovered, until orange slices are lightly charred, about 3 minutes per side. Serve chicken and orange slices with warm tortillas, pickled onions, and salsa.