01 - Season beef cubes evenly with salt and pepper on all sides.
02 - Heat vegetable oil in a large Dutch oven over medium-high heat. Working in batches to avoid overcrowding, sear the beef until browned on all sides, approximately 3-4 minutes per batch. Remove browned beef and set aside.
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 allow the sugar to dissolve and caramelize slightly.
05 - Return the beef to the pot. Add coconut milk, beef broth, and carrots. Bring to a gentle simmer, stirring to combine all ingredients.
06 - Reduce heat to low, cover, and braise for 1 hour. Maintain a gentle simmer throughout the cooking process.
07 - Add mushrooms, stir gently to incorporate, and continue to braise covered for another 1 to 1.5 hours, until beef is very tender and easily pierced with a fork.
08 - Remove and discard the lemongrass stalks. Stir in lime zest and juice. Taste and adjust seasoning with additional salt or fish sauce if needed.
09 - Serve hot over steamed jasmine rice or rice noodles, garnished generously with chopped cilantro, sliced scallions, and fresh lime wedges on the side.