Peel, quarter, core and slice the apples into 7mm segments. Put them into a stainless steel or enamel saucepan. Add the sugar, lemon rind and juice and sweet geranium leaves. Cover with a greaseproof paper lid and the lid of the saucepan; cook on a gentle heat until the apples are soft but not broken. They may be cooked in a moderate oven, 180°C/350°F/Gas 4, if that is more convenient.