If you prefer to finish cooking in the oven, preheat it to 325°F and position a rack in the lower third. Make sure your pot is oven-safe before proceeding.
In a large Dutch oven or heavy-bottomed pot, heat the oil over medium-high heat until it shimmers. Add half of the beef chunks and sear them until browned on all sides, about 6 to 8 minutes. Avoid overcrowding the pot for even browning. Transfer the seared meat to a large plate and repeat with the remaining beef. Set aside once all pieces are nicely caramelized.
Lower the heat to medium and add the sliced onion and minced garlic to the same pot. Sauté for 4 to 5 minutes, stirring occasionally, until the onions turn translucent and fragrant. Pour in the water, tomato sauce, soy sauce, and brown sugar. Add the bay leaves and black pepper, then stir to combine, scraping up any flavorful browned bits from the bottom.
Return the beef along with any collected juices back into the pot. Stir well to coat the meat with the sauce. Bring the mixture to a gentle boil over medium-high heat. Once boiling, cover the pot and either transfer it to the preheated oven or reduce the stovetop heat to maintain a steady simmer. Cook for about 1 hour and 20 minutes, allowing the flavors to meld and the meat to begin tenderizing.
After this initial simmer, add the potatoes and carrots to the stew. Gently mix them in to ensure they’re submerged in the broth. Scatter the bell pepper pieces evenly over the top. Cover once more and continue cooking—either in the oven or on the stovetop—for another 1 hour, or until the beef becomes fork-tender and the vegetables are soft but not falling apart.
Once done, remove the bay leaves if desired. Serve the hearty Filipino Beef Stew hot with a side of steamed white rice, letting the flavorful sauce soak through each bite.