Sweet Potato Soup with White Wine, Lime and Chillies

It's getting very autumnal and, for me, that means it's soup time. Recently I was listening to someone talking on the radio about how unusual it was to use wine in a soup. I wasn't convinced that it was that unusual and I began trying to remember any soups that I'd made with wine. From somewhere deep in my confused memory,  I recovered this one from the distant past.

It's a simple enough soup but if the balance between the sweet ingredients (the leeks and sweet potatoes) and the sharp ingredients (dry white wine and lime) is just right, then I think it's a bit special. The touch of chilli heat rounds it off very nicely for me. Of course, there are a lot of variables such as the size and sweetness of the sweet potatoes, so it's the perfect excuse to taste carefully and repeatedly before serving to your victims, sorry, I mean guests.

You could use any chilli paste or sauce you like in this soup but one with a good savoury flavour and maybe a little smokiness works best. I used an urfa chilli paste this time, but you could use something like a hot Turkish pepper paste (aci biber salçasi) or, if you're showing off, something homemade. Just don't use too much of it, or you'll mask the other flavours. It's best to start off with a small amount and add any extra you think it needs after tasting.

This will make around 5 lunch-sized portions but will fill a few more delicate, starter bowls.

2 large leeks, white part only, washed and cut into roughly 1cm rounds

3 garlic cloves, crushed

1 tsp ginger, puréed or very finely grated

1 - 2 tsp urfa chilli paste (see above for alternatives)

150ml dry white wine 

1 litre stock, use a chicken or a rich vegetable stock (or a combination)

2 large sweet potatoes, peeled and chopped into 1 - 2cm pieces

1 lime, juice only

Parsley or chervil and crisp fried onion or shallot, to serve 

Soften the leeks slowly in a little olive oil for about 10 minutes. Add the garlic and ginger and continue frying gently for 5 more minutes. Stir in the chilli paste and wine and reduce by about a half. Add the stock, some salt and pepper and the sweet potatoes. Cover and simmer for 30 - 40 minutes until everything is soft. 

Add half of the lime juice. Purée in a blender (or with a hand blender) until you get a smooth consistency and a suitable thickness. (You may need to add a little water). Taste and blend in as much of the reserved lime juice and any seasoning or additional chilli paste that you think it needs. 

Decorate with a sprinkling of finely-chopped parsley (or chervil if you have it) and a few crispy, fried onions or shallots.