As soon as we see the chestnuts at the grocers we snap them up for this delicious spanish soup. I have always made it with chorizo, using the recipe in Moro for a guide, but when we were in Italy staying with the wonderful Cole family I made it with a local random salame that had some fennel in it, and it was really good! I have also made it using squash instead of the chestnut (no need to pre-cook) and it was velvety, rich and gloriously bright orange. In fact, once you have mastered the art of a good soffrito, you can play around with which starchy veg and which salami you use.
No pictures of the soup itself because we took it up the road in a flask to a friend's bonfire night party. We stood in the street with bowls of the stuff steaming gently and taking advantage of a neighbour's firework display.
Approximate measurements only I'm afraid!
Sopa de Castanas (Chestnut soup)
1 stick of celery chopped finely
1 large white onion chopped finely
1 large carrot (2 small) chopped finely
3 cloves of garlic
a large chunk of chorizo or salame (approx 120g)
big pinch saffron infused in 3tbs hot water
2 tsp fresh thyme leaves (1/2 tsp dried)
2 tsp tomato puree
2 medium fresh tomatoes chopped
Roast the chestnuts in a hot oven until they are done (15-20 minutes) remembering to make a cut in the top so they don't explode in the oven. When they are cool enough, peel, chop and set aside until you want to make the soup. You can also use pre prepared chestnuts - but you won't get the same smoky flavour.
Saute the carrot, celery and carrot in a little oil gently in a deep heavy based pan until translucent. While this is happening, take the skin off the chorizo and cut it into small chunks and then add it to the pan and continue to saute gently for at least 20 minutes until the vegetables have taken on a deeper colour and started to caramelise.
Finely chop the garlic and add to the pan with the thyme leaves, stirring for 1 minute and then add the tomato paste, cooking for a couple minutes more until the tomato smell rises. Add the chopped chestnuts, fresh tomato and saffron water with all the bits, stir to coat and then add enough boiling water to cover everything by about an inch.
Bring up to a simmer, put a lid on and reduce the heat so everything bubbles away for about 15 minutes. Check that everything is nice and soft and then mash so that the soup still has texture - you're not aiming for smooth here. If it's too thick add a bit of water - too thin, just leave the lid off the pan and turn the heat up a little until the soup thickens up a little.
If the chorizo is mild you may want to sprinkle a few chilli flakes over the soup (pul biber or urfa biber are nice), also nice with a spoonful of Greek yogurt on top.