In a mixing bowl, combine 1/2 tablespoon sugar, pepper, and 1 tablespoon fish sauce. Mix well then add the beef slices and marinate for 10 minutes.
In a hot fry pan, add the vegetable oil and fry the garlic until fragrant. Add the beef slices and stir-fry for 1 minute then remove the beef and set aside.
Wipe the pan out. Add the choco to the same hot pan, then add the remaining 1 tablespoon fish sauce, 1/2 tablespoon sugar, and 1 tablespoon of water. Stir, then cover with the lid and cook on medium heat for 5 minutes.
Remove the lid, add the spring onions, cooked beef, and toss well for another minute.
In a small bowl, combine the sliced chile and soy sauce and set aside.
Transfer the beef mixture to a plate, garnish with coriander (cilantro) and serve with steamed jasmine rice and the chile-soy dipping sauce.