Mix the soy sauce, vinegar, and sugar in a bowl.
In another bowl mix bouillon cube, water, and cornstarch.
Assemble remaining ingredients.
Cook in a wok or heavy skillet, heat 1 1/2 tsp oil, add garlic and meat. Stir fry for 2 minutes (still should be slightly pink).
Remove meat and juices, discard garlic and wipe skillet.
Add 1 TBSP oil, when hot add onion and broccoli, cook for 2 minutes.
Pour in meat and juices, then pour in soy-vinegar mixture.
Stir, cover, and cook for 2 minutes.
Stir in bouillon and cornstarch mixture.
Stir, cover, and cook for 2 minutes until thick.