This recipe is adapted from Liana Krissoff's book, "Canning for a New Generation". It is a delicious jam which does not use too much sugar, and because of this the flavor of the fruit really shines through. If they are available, I like to use Meyer lemons for the juice and the zest, because they have such a nice fragrance. But if you can only find regular lemons they will work just as well. You will need a jelly bag or some cheesecloth to hold the apple cores and trimmings while they simmer in the jam. These will provide the pectin needed to help the jam set. You use the cold plate test to check the set of this jam. I have included instructions on how to do this below.