01 - Rub beef cubes thoroughly with kosher salt and black pepper, ensuring even coating on all sides.
02 - Heat vegetable oil in a large Dutch oven over medium-high heat. Sear beef in batches, turning until browned on all sides. Transfer browned beef to a plate and set aside.
03 - Add onion, lemongrass, garlic, ginger, and chilies to the same pot. Sauté for 3–4 minutes until fragrant and onions have softened.
04 - Stir in fish sauce and brown sugar, scraping up any browned bits from the bottom of the pot. Cook for 1 minute to meld flavors.
05 - Return seared beef to the pot. Pour in coconut milk, beef broth, and add carrots. Bring mixture to a gentle simmer.
06 - Reduce heat to low, cover tightly, and braise for 1 hour, maintaining a gentle simmer.
07 - Stir in quartered mushrooms, distributing evenly throughout the braising liquid.
08 - Continue braising covered for 1 to 1.5 hours longer, until beef is fork-tender and yields easily to pressure.
09 - Discard lemongrass stalks. Stir in lime zest and juice. Taste and adjust seasoning with additional salt or fish sauce if needed.
10 - Ladle braised beef and sauce into bowls. Garnish generously with chopped cilantro, sliced scallions, and lime wedges. Serve immediately with steamed jasmine rice.