Wash and cut you broccoli in 1 in. (2.5 cm) pieces, if you are using fresh broccoli. If using frozen, cut down any large florets.
In a large frying pan over medium heat, add the oil.
Mince or grate the garlic and add this to the pan. Cook until softened and just starting to colour.
Add in the broccoli and fry, stirring constantly, for about 3 minutes.
In a small bowl, mix together the soya sauce (or tamari sauce), sugar, stock, and cornstarch.
Turn the pan to medium-high, and add the sauce to the broccoli.
Stir the broccoli and sauce mixture until it comes to a simmer and starts to thicken and becomes clear.
Remove from heat and serve!