When it's cold outside, hot soup is a logical dish to serve because it's comforting and nutritious. Some of them take only minutes to prepare (think miso soup) while others require a lot more time and effort. These two recipes fall somewhere in between: they're not difficult, but they take a little time, although much of it is spent waiting for the ingredients to become tender. The seafood and chorizo soup is hearty enough to serve as a main course; the chestnut soup would make a delicious start to an elegant dinner.

Seafood and chorizo soup (pictured)

We used monkfish and mussels for this soup, but you can substitute other types of fish or shellfish.

1kg fish bones

2 large carrots, about 250 grams each, divided

2 celery stalks, divided

1 fennel bulb, about 300 grams

225 grams Spanish chorizo

500 grams potatoes (I use the smooth-skinned local potatoes)

50 grams unsalted butter

2 shallots

2 garlic cloves

4 anchovy fillets in oil, drained

300 grams monkfish fillets, cut into bite-size chunks

700 grams small mussels, preferably the variety with the blue-black shells (don't use green-lipped ones)

20ml Pernod or another anise-flavoured liqueur

Fine sea salt

Chives, Italian parsley or fennel fronds, to garnish

Rinse the fish bones under cold water, then put them in a large pan. Roughly chop one carrot, one celery stalk and the fennel bulb, put them in the pan and add 1.5 litres of water. Bring to the boil over a medium flame then lower the heat and simmer for an hour. Put a colander over a large bowl and strain the fish stock. Press on the bones and vegetables to extract as much flavour as possible, then discard the solids. Wash out the pan and dry it.

Slice the chorizo into discs about 5mm thick. Put them in an unoiled skillet set over a medium flame and cook until sizzling. Lower the heat and cook the chorizo until lightly browned, then flip over the pieces and brown the other side. Put the chorizo pieces on a plate; reserve the chorizo fat.

Peel the potatoes. Cut the potatoes and remaining carrot and celery stalk into 1cm cubes. Slice the shallots and garlic. Melt the butter in the washed-out pan, add the shallot and garlic and cook over a low flame until soft. Add the potato, carrot and celery and stir to coat with the fat. Finely chop the anchovies and stir them into the ingredients, then add the fish stock and the chorizo pieces. Bring to the boil over a medium flame then lower the heat and simmer for about five minutes. Add the monkfish, mussels and Pernod and simmer until the seafood is cooked (about five minutes). Taste the broth and add salt as necessary.

Ladle the soup into bowls and drizzle each portion with a little chorizo oil. Garnish with chives (cut into 5mm lengths), parsley leaves or fennel fronds, then serve with crusty bread.

Chestnut and potato soup

For this soup, buy roasted chestnuts from a street vendor; they're cooked with charcoal and sugar, so have a wonderful smoky flavour. If you can't find a vendor, you'll need to cook your own: buy the fresh chestnuts from the market, cut a deep X on the slightly pointed end of the hard shell. Cook the chestnuts at 200 degrees Celsius for about 30 minutes, or until tender. Some supermarkets also sell bags of cooked chestnuts from Japan or France, but these are expensive. With all kinds of cooked chestnuts, the shell and papery skin come off easiest if they're hot.

400 grams chestnuts

50 grams butter

3 shallots, about 25 grams each

2 large garlic cloves

One potato, about 300 grams

About 2 litres chicken or vegetable stock, preferably home-made

¼ tsp piment d'Espelette or cayenne pepper

250ml cream, divided

Fine sea salt and freshly ground black pepper

Remove the shell and papery skin from the chestnuts; if necessary, heat them in the oven or microwave (if using the latter, don't cook them too long or they might burst).

Finely chop the shallot and garlic. Peel the potato and roughly chop it.

Heat the butter in a soup pan and when it melts, add the shallot and garlic and cook over a low flame until soft. Sprinkle in the piment d'Espelette and about three-quarters of a teaspoon of salt and stir for about 30 seconds. Stir in the potato and chestnuts, then add 1.5 litres of the chicken or vegetable stock. Bring to the boil over a medium flame then lower the heat and simmer until the potato and chestnuts are very tender. Use a blender or food processor to purée the soup until smooth, then pour it back into the pan. Bring to a simmer and stir in 200ml cream; if it's too thick, add more stock. When the soup is simmering, taste it for seasonings and add pepper and some salt, if needed. Ladle the soup into bowls. Drizzle a little of the remaining cream over each portion, sprinkle with black pepper and serve.

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