How to cook
Wash the apples, dry them and cut them into pieces without peeling them or removing the seeds. Pour water over them in a pot, enough to cover them and press with a plate.
Boil them until softened but without over-boiling them. Strain the juice through a cheesecloth without mashing the fruits. Put the syrup to boil until it's reduced down to 4 1/5 cups (1 L).
Boil it on high heat in a container with a wide bottom, along with the sugar. Stir nonstop and remove the foam that forms.
Once ready, distribute the still-hot jelly into dry and heated jars. Close them and store the jars in a ventilated area.