Pour 4 tbsp oil in a pot and when its warm enough, add in the fennel and the mustard seeds until the mustard seeds pop.
Then add in the onions and fenugreek seeds until the onions becomes quite soft before browning.
(Optional) Add in the rinsed dried anchovies ("ikan bilis") roughly pounded, and curry leaves until the onions turn golden brown.
Stir in the chillies, potatoes and tomatoes.
Sprinkle some salt and a pinch of turmeric powder.
After a few minutes, add enough water to cover the vegetables.
When the potatoes are soft and tomatoes are mushy, add in the coconut milk.
The milk will simmer at the sides but do not let it boil or it curdles.
Taste for salt. Sprinkle the roasted and ground ingredients.
Add in the coriander leaves and stir for 1 minute.
Switch off the flame and continue stirring for a few minutes.
Allow it to cool slightly before you cover the sothi.
Best eaten with string hoppers or hot & spicy food.