Pit and puree all peaches and plums in a food processor. You will likely have to do it in stages since they won't all fit in one go.

Pour puree into a large, heavy bottomed stainless steel pot with one cup of sugar, lemon zest and lemon juice.

Cook over a medium heat for 15-20 minutes or until the fruit is very soft.

Place a large fine mesh sieve over a bowl and ladle that fruit into the sieve. Using a wooden push or the ladle, push the fruit through, leaving the skins and thicker pulp behind in the sieve. Wash the pot if you are making the candy in it in the next stages.

Pour the sieved mixture back into clean pot.

Add the rest of the white granulated sugar and the vanilla.

Cook over a medium heat for approximately 30 minutes or until the candy reaches the hard ball stage - 260 degrees F. This will give you firm but chewy candy that you can slice with a sharp knife.

When the candy reaches the desired temperature, pour it into a pan lined with parchment paper. Make sure the pan is large enough to hold the candy and for the love of God, don't touch the hot candy.

Leave the candy to cool for 12 hours.

Peel off the parchment paper and cut it into desired size morsels. Roll the cut candy in icing sugar and put it in a sieve. Shake the candy in the sieve to remove the excess icing sugar.

Store candy in an air tight jar. It will keep for quite a while, in theory. In practice it will be eaten quickly by friends and family.