This recipe is a great thing to do with the kids

�All visitors to Hampstead Heath know by now that there are armfuls of blackberries to enjoy – but don’t miss the less obvious late summer crop of wild apples.

Some of these are escaped varieties of domestic apple, with large and sweet fruits, and others are the little red handfuls of crab.

It’s not only the Heath that offers us wild apples, many north London streets are planted with malus sylvestris – prized for their blossom in the spring and now scattering their marvellous gifts of crab apples onto the pavements.

Pick them if you can reach somehow (from the roof of your car or the shoulders of a strong friend) or collect up the windfalls, then make them into the prettiest jelly in the world.

Making apple jelly is also the perfect project for children during the last few days of the summer holidays.

Wash the apples well and chop roughly. Don’t peel or core them as the pectin in the pips will help the jelly set beautifully. You don’t need to use preserving sugar, for this reason.

Put the chopped apples into a pan. Add water, not to cover, but about three-quarters of the way up the apples. Boil gently for about 30 minutes until the fruit is soft.

Then put the cooked apple mush into a jelly bag (an old pillowcase or a cloth save-the-planet bag) and suspended over a bowl overnight so the juices can drip into it.

The resulting liquid should then be measured and a pound of granulated sugar added to each pint of juice – easy to remember.

Add spice

At this stage, decide whether to add a spice. Cinnamon and chilli are highly recommended.

If you are ready to start thinking about Christmas presents, make extra – this makes a great gift.

Tie the spices in a piece of muslin and add to the brew.

Next, boil up your juice and sugar in your biggest pan and boil it fast.

It has reached its setting point when a few drops put onto a cold saucer (out of the freezer) can be made to wrinkle when you push them with your finger. If it doesn’t wrinkle, keep on boiling.

Some frothy scum will form on the surface of the jelly. Scoop this off and keep for your toast. We are aiming for crystal clear jelly so this is important.

Pour into heated and scrupulously cleaned jars, which you have sterilised in the oven or with boiling water. Pay particular attention to the lids, which can trap bacteria. When it is cool, add waxed discs to the jelly to keep the mould at bay.

Enjoy decorating the labels and savour the pink jelly lined up with the light shining through it. This is indeed a gem for the delight of urban foragers.

The nearest side street around the corner from my house is covered in crabs and would keep every resident in jelly for their roast meat all winter if they desired it. My ambition is to put a jar onto each doorstep on Christmas Eve.