1- First of all, put your all ingredients on the work table. Secondly, wash your damson plums. If you have picked them yourself double check of any holes or blemishes and remove the debris and stalks etc. Then, If you are using a knife to remove the seeds (stones), remove them from the plums and cut into halves (or quarters). Then, layer your plums and 1 cup of sugar in a saucepan overnight (your damson plums release their juice until the morning, if not, add extra water when cooking).
2- The following day place the damson plums in a medium size pot and add rest of the sugar and 1 teaspoon butter (it helps to decrease foam, when your jam boiling). Then, start cooking mixture of Damson plums and sugar on medium heat and stir with the wooden spoon until the sugar dissolves (melts). If it happens, remove the scum or foam from the surface. Keep cooking the jam mixture for about 40 minutes or until the your damson plums has completely fallen apart and stirring continuously to avoid boil-overs.
3- Then, add the lemon salts and stir (if you want, you can add lemon juice). And continue cooking the jam until it reaches gel stage (it takes nearly 10 minutes).
4- Then, remove the damson plums pot from the heat and cool for a few minutes, Lastly, pour your damson plum jam carefully into clean glass jars. Close the lid and let it cool. Then, store in a dark and cool place or store in the refrigerator.
5- You can serve damson plum jam as an ice cream topping with Turkish homemade baklava dessert or on biscuit topping or on cookies topping.