Prep the Beef:

Pat beef cubes dry with paper towels and season generously with salt and pepper.

Sear the Beef:

Heat vegetable oil in a Dutch oven or heavy-bottomed pot over medium-high heat.

Sear beef cubes on all sides until well browned. Don’t overcrowd the pan — work in batches if needed.

Transfer browned beef to a plate.

Sauté Aromatics:

Reduce heat to medium. Add chopped onion and cook for 5–7 minutes, until soft.

Stir in garlic and ginger; cook for 1 minute until fragrant.

Braise the Beef:

Return beef to the pot. Add soy sauce, beef broth, brown sugar, rice vinegar, and red pepper flakes (if using). Stir to combine.

Bring to a gentle simmer, then reduce heat to low. Cover tightly and braise for 2 to 3 hours, or until beef is fall-apart tender.

Check occasionally and add more broth if liquid runs low.

Make the Glaze:

Once beef is tender, remove the lid.

In a small bowl, whisk cornstarch and cold water to make a slurry.

Stir slurry into the sauce and simmer for 2–3 minutes, or until the sauce thickens to a glossy glaze.

Serve:

Spoon sticky glazed beef over steamed rice or noodles. Drizzle with extra sauce and garnish as desired.