Heat your oven to 200C then place your cauliflower florets onto baking paper on an oven tray and roast for 30 to 40 minutes.
While that's happening - Make your sauce. Combine 1 cup water, soy or tamari sauce, brown sugar, ginger and garlic powder in a saucepan over medium heat. Cook until nearly heated through, about 1 minute. And while that's happening... Mix cornstarch and 1/4 cold water together in a cup; stir until dissolved. Add to the saucepan. Cook and stir sauce until it thickens 5 to 7 minutes.
Once your cauliflower is cooked through, remove from the oven and place in a bowl and pour the sauce over it and gently stir through. Adding and stiffing in the white part of the spring onion and then sprinkle green part and the sesame seeds as a garnish.
This recipe welcomes some tofu so feel free to add some in along with some rice and you'll have a main course :)