Wash cauliflower florets thoroughly in water.
Boil 4 cups of water with 1/2 tsp salt. Add in the cauliflower florets and switch off the stove.
Allow the florets to rest in water for 5 mins.
Drain the water using colander. Bring the cauliflower florets under cold running water. Drain all the water.
Mix all purpose flour, corn flour, rice flour, red chilli powder, salt. To this add about 1/2 cup of water and prepare batter with no lumps. Batter should be thick enough to coat the cauliflower florets.
Heat oil for deep frying in a deep bottomed pan keeping the heat medium. Dip the cauliflower florets in prepared batter and drop it into oil. Fry both sides till it turns golden.
Once fried remove it to a plate.
Meanwhile when cauliflower is frying, heat 2 tablespoon sesame oil in a wide pan. Add chopped onion, minced ginger, garlic in medium high heat till it turns golden.
Add green chilli and fry for a minute.
Now add in tomato ketchup, soy sauce, chilli sauce, vinegar, little salt and give a good mix keeping heat medium.
Add capsicum pieces and fry for 2 mins.
Add fried cauliflower pieces, toss well and switch off the stove.
Finally garnish with spring onions/ scallions. Gobi manchurian is ready to be served.