In a jug or bowl, dissolve the yeast in 50ml warm water and leave to bubble for 15 mins.
Put the flour and sugar in a bowl with a pinch of salt. Add the coconut water and milk, whisking continuously to avoid lumps, then add the yeast mixture and mix until you have a smooth batter. Cover with cling film and leave to ferment for 2 hrs.
When it’s time to cook the hoppers, whisk the base mixture to remove any lumps. It should be the consistency of double cream, so add a splash more coconut water to thin it if needed. Heat a lidded, non-stick frying pan or small, lidded, high-sided wok until very hot and brush on a little sesame oil with kitchen paper. Add a ladleful of mixture to the pan and immediately swirl it around and up the edges to create a bowl-shaped pancake. Cook, uncovered, for 1 min, then cover with a lid. Cook for 2-3 mins more until the edges are starting to crisp and the base is cooked through. Remove and set aside, then repeat with the remaining batter. Serve with the cauliflower curry, leek seeni sambol and chutney (see goes well with).