Converted from a recipe in the local paper, which was converted from an authentic recipe that I've never seen. The original has prawns, but we vastly prefer it without. It's excellent for Lent when you're fed up with drab-looking and unsubtle-tasting food. Also, it's very easy.
If you use asafoetida, make sure that you don't have the kind that's mixed with turmeric (sold as "hing" in Asian shops) because you really don't want the taste of turmeric in this soup. It's very hard (at least in the Netherlands) to get real unadulterated asafoetida, but a little goes a long way: you don't need more than a grain the size of a match-head where you would use a teaspoonful of shrimp paste to have the same effect.
Mince onion and pepper very small and rub it and the shrimp paste or asafoetida into a rough puree in a mortar, or give it a short whirl in a blender. Bring a little coconut milk to a rolling boil in a large pan, stir in the puree, then add the pumpkin and the rest of the coconut milk. Cook until the pumpkin is falling-apart tender, about 20 minutes.
Put everything through a sieve or passe-vite, put it back in the pan and add the stock. Finish with lime juice and (optionally) salt. If you want to add prawns, do it now and heat through for a few minutes.