See images above for guidance. Also, you don't have to do this step if you can remove the peach skins easily as they are. Often ripe peach skins come off very easily. You can use a paring knife to help.

Put your peaches into a pot of boiling water, for 1 minute. No longer.

Then remove from the boiling water, and immediately put them into a cold water bath, for 1 minute. No longer. Do not soak them.

The skins should just peel off.

Peel off the skins.

Once the skins have been removed, take out the pits, and slice the peaches.

Place the peach slices, lemon zest and lemon juice into a large pot or skillet.

Over medium-low heat cook for about 15 minutes, until the peaches are soft, and the juices are released.

As the peaches soften, stir frequently, and use your spoon or a potato masher to break them down.

At this point, add the sugar, and stir until dissolved.

On medium-high heat, bring the mixture to a boil, cook for 5 minutes, stirring continuously.

After the 5 minutes, reduce the heat to low-medium (don't boil the jam, just slow cooking), for another 40 - 60 minutes. You will know that the jam is ready when the mixture is thick enough to leave a trail behind the spoon. NOTE: the jam will also thicken as it cools, so be careful not to overcook it.

Remove from heat, and let cool.

Add to a jar with a lid and refrigerate.