Start by removing all the giblets and excess fat from your chicken (Alisin ang laman-loob at sobrang taba ng manok). Rinse the chicken thoroughly under cold running water and pat it completely dry using paper towels. This step is crucial for achieving crispy skin (Para maging malutong ang balat).
Make small cuts across the chicken's skin using a sharp knife (Gawin ang maliliit na hiwa sa balat). This will help the marinade penetrate deeper into the meat. Season the entire chicken, including the cavity, with salt and pepper (Timplahan ng asin at paminta ang loob at labas ng manok).
In a large mixing bowl, combine calamansi juice, fish sauce (patis), soy sauce (toyo), and brown sugar (asukal na pula). Stir continuously until the sugar completely dissolves. Add your minced garlic (tinadtad na bawang) and shallots (sibuyas tagalog) to the marinade mixture. Mix everything thoroughly.
Place your seasoned chicken in the marinade, making sure it's well-coated (Ibabad ang manok sa marinade). Massage the marinade thoroughly into the skin and cavity. Cover your marinating chicken and place it in the refrigerator. Allow it to marinate for 4-8 hours at 4°C/39°F, turning the chicken every 2-3 hours to ensure even flavor distribution (Baliktarin ang manok kada 2-3 oras para pantay ang pagkakalambot).
Thirty minutes before cooking, remove the chicken from the refrigerator and let it reach room temperature (Ilabas ang manok sa ref 30 minuto bago lutuin). During this time, prepare your lemongrass by bruising it with the back of a knife, then cut it into 3-inch pieces. Stuff these pieces into the chicken's cavity (Ilagay ang tanglad sa loob ng manok).
Preheat your turbo broiler to 180°C/350°F (Initin ang turbo sa 180°C). Place the chicken breast-side down and cook for 20-30 minutes, basting with the reduced marinade every 10 minutes (Pahiran ng marinade kada 10 minuto).
After the initial cooking period, carefully flip the chicken so it's breast-side up. Continue cooking at 180°C/350°F for another 20-30 minutes, maintaining your basting schedule.
For the final stage of cooking, increase the temperature to 215°C/420°F (Pataasin ang init sa 215°C). Cook for a final 10-15 minutes until the skin turns a beautiful golden brown and becomes crispy (Lutuin hanggang maging golden brown at malutong ang balat).
The chicken is done when a meat thermometer inserted into the thickest part reads 74°C/165°F (Luto na ang manok kapag umabot sa 74°C ang temperatura sa loob). The juices should run clear when you tilt the chicken, and the joints should move easily.
Let your lechon manok rest for 15-20 minutes before cutting. This resting period allows the juices to redistribute throughout the meat, ensuring every bite is moist and flavorful (Para masiguradong makatas ang karne).
Serve your lechon manok hot with toyomansi sauce (toyo at kalamansi) on the side. Traditional accompaniments include steamed rice (kanin), cucumber slices (pipino), and atchara (pickled papaya). Store any leftovers in an airtight container in the refrigerator for up to three days, or freeze for up to two months. When reheating, warm in a preheated oven at 177°C/350°F for 15-20 minutes to maintain the crispy skin.