Soak the basmati rice and parboiled rice in a large bowl of water for 6 hours.
At the same time, soak the lentils and fenugreek seeds in another large bowl of water for 6 hours.
Drain the rice.
Transfer to a blender or food processor and process, gradually adding about 500ml / 18fl oz (2 1/4 cups) water to make smooth batter. Transfer to a bowl.
Drain the lentils, transfer to a blender or food processor and process, gradually adding 2-3 tablespoons water to make a smooth batter.
Combine both batters, season with salt and set aside to ferment for 6-8 hours.
The batter should be of a thick pouring consistency, so add a little more water, if necessary.
Heat the 2 tablespoons oil for the tempering in a frying pan (skillet).
Add the mustard seeds and stir-fry for 1 minute, or until they start spluttering, then add the onions and fry for a further 1-2 minutes.
Mix in the coconut and fry for 1 minute. Stir the contents of the pan into the batter and mix in the coriander leaves.
Heat a dumpling pan and fill each depression with a little oil.
When heated, add enough batter to come halfway up the depressions and fry over low heat for about 3 minutes.
Turn the dumpling over gently with a skewer and fry the other side for about 3 minutes, or until golden.
Remove and drain on kitchen paper (paper towels).
Serve with Coconut Chutney.
You will need a special paniyaram pan for this dish, but a Danish aebleskiver pan, used for making Danish-style pancakes, is a perfect substitute. You could also use an egg poacher.