Into the blended/grounded ingredients, mix in the curry powder and tomato puree. Heat oil and when heated, add this mixed ingredients as well as cumin and mustard seeds. Fry and stir until the oil float, then add 1/2 liter of water, curry leaves and salt to taste. Stir and simmer until curry is heated through before adding cauliflower and lemon juice. The curry is done once the cauliflower is cooked.