Blanche the cauliflower and brocolli together (boiled for around 3 minutes until half cooked and transfer to iced water. Take out when cooled completely to go back to room temperature).
Heat the oil in a pan and stir fry the chicken for around 5 minutes until golden. Do this is batches. Transfer to kitchen towel to drain off excess oil.
Stir fry the onions, peppers and mushrooms for 5 minutes. Add the paste and water and bring to boil. Turn down the heat and simmer with a lid on for 5 minutes. Add the brocolli and cauliflower and simmer for another 5 minutes. Serve with rice or some yummy naan bread.