Bring a large bowl with water and salt to a boil. Add the cauliflower florets and cook for 1 minute.
Immediately remove the cauliflower from the boiling water and run over cool water. Set aside in a colander to drain and place them on kitchen towel to remove excess water.
Mix all purpose flour, 1 tbsp cornflour, salt, ginger garlic paste and 1 tbsp soy sauce in a bowl. Add some water if necessary to make a thick paste.
Add the florets and mix well. Marinate this for at least half an hour.
Heat oil for frying in a pan and deep fry the marinated and coated cauliflower pieces till golden brown. Do not over crowd the pan as the coated florets tend to stick to each other.
Remove them from fire and set on paper towel to remove excess oil.
Heat 2 tbsp oil in a pan on medium high heat and fry the onion, green chili and garlic lightly.
Toss in the fried floret pieces and cook for a couple of minutes.
Add the tomato puree and mix well.
Take the remaining 1 tbsp corn flour in half a cup of water and add this to the cauliflower. Cook till all the gravy is coated well to the florets and becomes dry.
Add in the vinegar, remaining soy sauce and spring onions and give it a stir and remove from flame.
Serve hot with veg fried rice and veg manchurian gravy.