01 -
Pat beef cubes thoroughly dry using paper towels. Season liberally with salt and black pepper.
02 -
Heat vegetable oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Sear beef cubes on all sides in batches, ensuring not to overcrowd the pan. Transfer browned beef to a plate.
03 -
Reduce heat to medium. Add chopped onion to the pot and cook, stirring occasionally, for 5-7 minutes until softened. Add minced garlic and grated ginger; cook for 1 minute until fragrant.
04 -
Return seared beef to the pot. Pour in soy sauce, beef broth, brown sugar, rice vinegar, and red pepper flakes. Stir thoroughly to combine ingredients, ensuring beef is mostly submerged.
05 -
Bring to a simmer, then reduce heat to low and cover. Cook gently for 2 to 3 hours until the beef is exceptionally tender, checking periodically that liquid covers the beef. Add a splash of beef broth if necessary.
06 -
Uncover pot once beef is fork-tender. In a small bowl, whisk cornstarch with cold water until smooth. Slowly add the slurry to the simmering pot, stirring constantly. Continue to simmer and stir for 2-3 minutes until sauce thickens and becomes glossy.
07 -
Serve glazed beef pieces immediately, spooning extra sauce over the top. Accompany with rice or noodles if desired.