Start by preparing the lemongrass (tanglad). Remove the tough outer layers of the lemongrass stalks and keep only the tender white portions (puting parte ng tanglad). Finely mince these portions and lightly pound them to release their aromatic oils (pisilin para lumabas ang sabaw).
In a large non-reactive bowl, combine the minced lemongrass with minced garlic (bawang), grated ginger (luya), palm vinegar (sukang paombong), calamansi juice (katas ng kalamansi), brown sugar (asukal na pula), salt (asin), and black pepper (paminta). Mix these ingredients thoroughly until the sugar completely dissolves (hanggang matunaw ang asukal).
Clean your chicken pieces thoroughly (linisin mabuti ang manok) and pat them dry with paper towels (patuyuin gamit ang paper towel). Make small cuts or scores in the meatier parts of the chicken to help the marinade penetrate better.
Place the chicken pieces in the marinade, making sure each piece is well-coated (siguraduhing nalubog sa marinade ang bawat piraso). Cover the bowl with plastic wrap or a lid and refrigerate. Let the chicken marinate for at least 4 hours, but no more than 24 hours (ibabad sa ref ng 4 oras hanggang 24 oras).
While the chicken is marinating, prepare the annatto oil. Place the chicken skin and fat in a pan over medium-low heat (150°C/300°F). Cook until the fat renders and the skin becomes crispy (hanggang lumabas ang mantika at lumutong ang balat), about 15-20 minutes. Add the annatto seeds (atsuete), crushed garlic, and bay leaf (dahon ng laurel). Continue heating for 2-3 minutes until the oil turns a deep orange color. Remove from heat and let it steep for 1 hour. Strain the oil and set aside.
Prepare your grill to medium-high heat (180-200°C/350-400°F). If using an oven, preheat to 190°C/375°F. Remove the chicken from the marinade and discard the excess marinade. Pat the chicken pieces lightly with paper towels to remove excess moisture (patuyuin muli ng konti).
Place the chicken pieces on the grill skin-side up first (balat ang nakaharap sa itaas). Let them cook for 8-10 minutes before turning. While grilling, baste the chicken generously with the prepared annatto oil every 5 minutes (pahiran ng mantikang atsuete kada 5 minuto). Turn the chicken pieces occasionally to ensure even cooking and to prevent burning.
Continue grilling for 30-40 minutes total, or until the chicken is fully cooked. To check doneness, insert a meat thermometer into the thickest part of the chicken – it should read 74°C/165°F (siguruhing naluto ang loob ng manok). The skin should be crispy and golden-orange in color, while the meat should remain juicy.
Once cooked, let the chicken rest for 5-10 minutes before serving (palamiginin ng konti bago ihain). This allows the juices to redistribute throughout the meat, ensuring each bite is moist and flavorful.
Serve your chicken inasal hot with steamed rice (mainit na kanin), and prepare the traditional condiments: spiced vinegar (sinamak) and soy sauce-calamansi mixture (toyomansi). Drizzle additional annatto oil over the rice if desired.
For best results when reheating leftovers, warm in a preheated oven at 150°C/300°F for 15-20 minutes, covered with foil to retain moisture (takpan ng foil para hindi matuyot). Always ensure reheated chicken reaches a safe temperature of 74°C/165°F before serving.