Heat oil in a wok or a deep fryer
In the meanwhile, dissolve the corn flour and all purpose flour along with pepper and salt in water.
Add the cauliflower florets and mix until the florets get coated with the flour mixture.
Add about 5 florets (or the amount your deep fryer /wok can hold) at a time into the hot oil and fry until golden brown.
Remove from oil and drain in paper towels. Keep aside.
Method for Sauce
Mix the corn flour with ¼ cup of water. Add soya sauce, ketchup and salt.
Heat oil in a wok or frying pan on high heat; add garlic, ginger, green chillies, spring onions and stir fry for a few seconds.
Add the corn flour mixture to the above and cook for a few minutes until thick and the corn flour is cooked.
Turn off heat.
Serving the Manchurian with Sauce
Just before serving, put the fried Manchurian in the sauce and stir fry on high heat for few minutes. Garnish with spring onion leaves and serve hot.