This jam is easy to prepare and does not need to stand at the stove for a long time. Thus, you can cook any jam from berries.
Remove the core from the apples, cut into slices, transfer to a saucepan with a thick bottom and cover with sugar. Leave for 30 minutes, apples should give juice.
Bring to a boil, reduce heat and simmer for 5-10 minutes. Remove from heat until cool (overnight).
Repeat the procedure 2-3 more times. The last time it is possible to cook longer, about 30 minutes. Transfer the jam to sterilized jars and close.
With this method of cooking, apples do not boil soft, but slices remain, the berries remain intact.