Pam Corbin's (River Cottage) fruit leathers are addictively simple to make – once you've made one, you'll soon be experimenting (apricots, plums and peaches all make good leathers). Cut off strips to add a healthy, fruity punch to lunchboxes and picnics. Makes two sheets.

500g blackberries
500g cooking apples, peeled, cored and chopped
Juice of 1 lemon
150g honey
A little groundnut oil, for greasing

Preheat the oven to very low – 60C/gas mark ⅛ is good, though the lowest setting you can manage is fine. Put the blackberries, apples and lemon juice in a pan, cook gently, partially covered at first, until soft and pulpy, about 20 minutes. Rub through a sieve or mouli into a bowl – you should have about 700g smooth purée. Mix in the honey.

Divide between two baking sheets lined with oiled baking parchment or foil, spreading out the purée thickly with a spatula until the sheets are covered with a smooth, even layer about 5mm deep. Bake for 10-12 hours, until it is completely dry and peels off easily. Roll up in greaseproof paper or clingfilm, store in an airtight container in a cool place and use within four months; or freeze it, well sealed, for up to a year.