The easiest way to pit cherries is to use a special instrument invented for the purpose. One arm has a little perforated 'cup' for cradling the cherry, the other a tiny 'lance' for skewering the cherry and forcing the pit out.

Remove the stem (if any) and place the cherry in the little cup, the stem end facing the lance, and squeeze both arms together. Ideally, the pit should simply pop out though the hole in the cup. Sometimes this doesn't actually happen, but no worries, the cherry will have opened up enough so that you can easily remove the pit by hand. Proceed to cut or simply tear the cherry in two.

Place all your cherries in a large mixing bowl as you go. When you're done pitting and splitting the cherries, add the sugar, lemon juice and zest. Mix well and let the cherries rest for several hours or, even better, overnight.After its rest, the cherries should have given off quite a bit of their own liquid.

Place the cherries and their liquid in a saucepan. Simmer, covered, for about 20-30 minutes, or until the cherries are quite soft and the liquid has thickened enough so a wooden spoon will leave an open trail behind it when you scrape it along the bottom of the saucepan. Fish out the lemon zest and let the cherries cool for a few minutes.

Now you have different options depending on the texture you like best. To make a proper jam with a smooth texture, pass the cherries though a food mill. Or, if you're like me and like the chunkier texture of a preserve, use a hand blender and blend until you have a rough but fairly consistent paste. Or if you like it chunky, blend about half the cherries and leave the other half as is.

Let the cherry preserves cool completely and transfer them to a jar or other container for safe keeping.