Cut the cauliflower into florets about 50 x 10 mm. Soak them in water for at least 30 minutes.
Peel and cut the potatoes into 20 mm cubes. Heat the oil and fry the potato cubes until brown on all sides. Remove the potatoes and keep aside.
Then add the mustard and fennel seeds. When the mustard seeds pop, add the garlic. Stir fry until the garlic changes colour then add the turmeric and chilli powder. Stir once and add the reserved potatoes, cauliflower, salt and water.
Stir fry for 5 to 6 minutes or until the potatoes are cooked through. Remove from the heat and stir in the coriander.