Cauliflower with chilli and mustard

From : http://www.taste.com.au/recipes/27328/cauliflower+with+chilli+and+mustard?ref=collections,cauliflower-recipes

Ingredients
60ml (1/4 cup) vegetable oil
1 brown onion, halved, thinly sliced
2 garlic cloves, thinly sliced
3 long fresh green chillies, thinly sliced
2 tsp mustard seeds
1 tsp ground turmeric
1kg cauliflower, cut into large florets
125ml (1/2 cup) water
1 tsp tamarind puree

Step 1
Heat the oil in a wok over medium-high heat. Cook the onion, stirring occasionally, for 7 minutes or until soft and golden. Add the garlic and chilli and cook, stirring occasionally, for 2 minutes or until aromatic. Add the mustard seeds and turmeric and cook, stirring, for 30 seconds or until aromatic and the mustard seeds pop.
Step 2
Add the cauliflower and stir to coat. Add the water and tamarind puree and simmer for 4 minutes or until the cauliflower is tender crisp. Season with salt. Transfer to a serving dish.