Kissel

Bring the fruit and the litre of water to the boil in a large pan.

Simmer for 8-10 minutes, until the fruit has burst and the liquid is deeply coloured.

Strain through a sieve into a clean pan. Let it drip for a clear kissel, or push the pulp through with a ladle for a thicker, cloudier one.

Stir in the 120g of sugar and the lemon juice until dissolved.

Taste it now and pull it a shade sweeter and sharper than you want the finished drink. Starch mutes flavour noticeably once it sets.

Decide the thickness before you measure the starch. Per litre of liquid: 20-25g gives a drink you pour into a glass, 40g a pouring sauce thick enough to coat the back of a spoon, and 70-80g a set pudding you eat with a spoon. The quantity here is the middle one.

Whisk the potato starch into the 60ml of cold water until no grit is left on the bottom of the bowl.

It settles again within a minute, so whisk it once more immediately before it goes in.

Bring the fruit liquid back to the boil, then take the pan off the heat and wait for it to stop bubbling.

Pour the slurry in in a thin stream, stirring the whole time.

Return the pan to low heat for 20-30 seconds, stirring, just until it thickens and turns from cloudy to clear and glossy.

Stop there and take it off. Potato starch sets at a low temperature and its gel is fragile: held at a boil, the swollen granules rupture, the kissel thins and turns stringy, and no further cooking brings it back.

Cornflour can be used instead at the same weight, but it needs a full minute at a simmer to lose its raw taste and gives an opaque, shorter set rather than a clear one.

Pour into glasses or bowls.

Dust the surface with the teaspoon of sugar, which dissolves into the surface moisture and stops a skin forming as it cools.

Serve warm, or chill for a couple of hours and serve cold. It thickens further in the fridge, so make it looser than you want if it is going in there.