01 - Season beef cubes generously with kosher salt and black pepper, ensuring even coverage on all sides.
02 - Heat vegetable oil in a large Dutch oven over medium-high heat. Sear beef in batches until deeply browned on all sides, approximately 3-4 minutes per batch. Transfer browned beef to a plate.
03 - In the same pot, add onion, lemongrass, garlic, ginger, and chilies. Sauté for 3-4 minutes until fragrant and onions are softened, stirring occasionally to prevent burning.
04 - Stir in fish sauce and brown sugar. Cook for 1 minute to dissolve sugar and meld flavors.
05 - Return beef to the pot along with accumulated juices. Add coconut milk, beef broth, and carrots. Bring to a gentle simmer, stirring to combine.
06 - Reduce heat to low, cover tightly, and braise for 1 hour. Maintain a gentle simmer with minimal bubbles breaking the surface.
07 - Add quartered mushrooms and stir gently to incorporate. Continue braising covered for another 1 to 1.5 hours until beef is fork-tender and mushrooms are silky.
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 - Ladle hot braised beef into bowls over steamed jasmine rice. Garnish generously with chopped cilantro, sliced scallions, and fresh lime wedges.