Heat cooking oil in a large pan over medium heat. Stir fry chicken, stirring occasionally until lightly browned and crisp.
In a small jug or bowl whisk together the soy sauce, sugar, vinegar and sesame oil to combine. Set aside.
Add the garlic to the centre of the pan and saute until lightly fragrant (about 30 seconds). Pour in the sauce and allow to cook, while stirring, until the sauce thickens into a beautiful shiny glaze (about 2-3 minutes).*
Add in the steamed broccoli. Garnish with green onion (or shallot) slices and serve over steamed rice.