Clean the beef and cut it into bite-sized cubes. Marinate with 1 tsp oyster sauce and let it sit for 20 minutes.

Peel and wash the potatoes and carrots, then cut them into pieces similar in size to the beef. Clean the celery and cut it into sections.

In a deep pot, sauté the beef with a little cooking oil (add a bit of water to prevent burning). Add enough water to cover the beef, bring to a boil over medium heat, then reduce to low heat and simmer until the beef is just tender (do not overcook).

Add the potatoes and carrots, season with salt and seasoning powder, and add enough water to cover. Simmer over low-medium heat until the vegetables are tender (by then, the beef will be perfectly tender).

Add the celery, increase to medium-high heat, and once the soup boils, turn off the heat.

When serving, garnish with a few sprigs of cilantro on top. Serve hot with toasted bread.