Peel and core the apples, cut into 12 even wedges, then slice thinly.
Combine apples, sugar and lemon juice in a saucepan, briskly stir, then let sit for about 30 minutes.
Once the apples start to release moisture, simmer on low heat. Remove any scum that rises to the top.
When the apples become translucent and there is still some liquid, it's ready.
How to jar the jam: Layer a pot with cloth at the bottom, fill it with plenty of water, then put in the washed jars and lids. Be sure to put the jars in before boiling the water.
Boil water for 2 to 3 minutes. Remove from the boiling water and dry.
After filling the jars with jam, lightly cap the lids, and steam in pot for 15 minutes.
Remove the jars, and tightly close the lids to seal. Cool at room temperature, then store in the refrigerator.