Bring a pot of water to a rolling boil, add a few drops of oil and a dash of sugar. Scald cauliflower in the hot water for 3 to 4 minutes. Remove, drain and soak in cold water for 4 to 5 minutes. Add carrots to the hot water and scald for 2 to 3 minutes. Drain and do the same as for cauliflower.
Heat oil and sesame oil in a wok, fry ginger till fragrant then add in garlic and saute till almost golden. Add prawns, squids, cuttlefish and the rest of the vegetables. Mix in seasoning and fry briskly for 4 to 5 minutes. (Do not overcook vegetables.) Stir in thickening and add a dash of sesame oil for glaze.