Begin by preparing your ingredients (Magsimula sa paghahanda ng mga sangkap). Cut the pork belly into 2-inch cubes. Set aside.
Prepare all vegetables (Ihanda ang mga gulay). Peel and cut potatoes and carrots into 1-inch cubes. Finely chop the onions. Mince the garlic. Remove the seeds from bell peppers and cut into 1-inch squares.
Place a large, deep pan or kawali over medium-high heat (190°C/375°F). Pour in the cooking oil and allow it to heat up until shimmering but not smoking (Initin ang mantika hanggang mainit ngunit hindi umuusok).
Once the oil is hot, fry the potato cubes until lightly golden brown, about 5-7 minutes. Remove with a slotted spoon and set aside. Do the same with the carrot cubes. Lastly, quickly sauté the bell peppers for just 30 seconds to retain their crispness. Remove and set aside with other vegetables.
In the same pan, lower the heat to medium (175°C/350°F). Sauté the minced garlic until fragrant but not brown, about 1 minute (Igisa ang bawang hanggang bumango). Add the chopped onions and continue sautéing until translucent, about 2-3 minutes (Idagdag ang sibuyas at igisa).
Increase heat back to medium-high. Add the pork cubes and cook until browned on all sides, about 7-10 minutes. Add the fish sauce (patis) and cook for another 2 minutes, stirring occasionally.
Pour in the tomato sauce and tomato paste. Stir well to combine. Add the water and bring to a boil. Once boiling, lower the heat to a gentle simmer (150°C/300°F) and cover the pan (Takpan ang kawali). Let it cook for 45 minutes, stirring occasionally to prevent the bottom from sticking (Haluin paminsan-minsan upang hindi dumikit sa ilalim).
Check the pork's tenderness by piercing with a fork. The meat should be very tender but still hold its shape. If needed, continue cooking for another 10-15 minutes.
When the meat is tender, add back the fried potatoes and carrots. Simmer for 10-12 minutes or until the vegetables are cooked through but still firm (Pakuluan hanggang maluto ang mga gulay ngunit hindi malambot).
Add the bell peppers last and cook for just 2 minutes to keep their bright color and slight crunch (Ilagay ang sili at lutuin ng dalawang minuto lamang).
Taste and season with salt and pepper as needed (Timplahan ng asin at paminta kung kinakailangan).
Let the dish rest for 5-10 minutes before serving. This allows the flavors to meld and the sauce to thicken slightly.
Serve hot over steamed white rice. Provide patis (fish sauce) and calamansi on the side for additional seasoning according to taste.
For storing (Para sa pag-iimbak): Let cool completely before transferring to an airtight container. Keep in the refrigerator for up to 3-4 days. When reheating, use medium heat (175°C/350°F) and add a small amount of water if the sauce has thickened too much.
Pork Afritada tastes even better the next day, as the flavors have more time to develop (Mas masarap ang afritada kinabukasan dahil mas nalalasahan ang mga sangkap).
Note: If the sauce becomes too thick during cooking, add hot water ¼ cup at a time. If too thin, simmer uncovered for a few extra minutes until it reaches your desired consistency (Kung masyadong malapot ang sarsa, dagdagan ng mainit na tubig. Kung masyadong malabnaw, pakuluan hanggang sa maging tamang lapot).