01 - Season beef cubes evenly with kosher salt and black pepper, ensuring all surfaces are coated.
02 - Heat vegetable oil in a large Dutch oven over medium-high heat. Working in batches to avoid overcrowding, sear the beef cubes until deeply browned on all sides. Remove browned beef and set aside on a plate.
03 - In the same pot, add onion, lemongrass, garlic, ginger, and red chilies. Sauté for 3–4 minutes, stirring frequently, until fragrant and onions have softened.
04 - Stir in fish sauce and brown sugar, cooking for 1 minute to allow the sugar to dissolve and flavors to meld.
05 - Return the seared beef and any accumulated juices to the pot. Pour in coconut milk, beef broth, and add carrots. Bring the mixture to a gentle simmer, stirring to combine.
06 - Reduce heat to low, cover tightly, and braise for 1 hour. Maintain a gentle simmer throughout.
07 - Add quartered mushrooms and stir gently to incorporate. Cover and continue braising for another 1–1.5 hours, or until beef is fork-tender and yields easily to pressure.
08 - Remove and discard lemongrass stalks. Stir in lime zest and juice. Taste and adjust seasoning with additional salt or fish sauce if needed.
09 - Serve immediately over steamed jasmine rice or rice noodles, generously garnished with fresh cilantro, sliced scallions, and additional lime wedges on the side.