500 g/ 1 lb sweet cherries
200 g/ 7 oz/ 1 cup granulated sugar
1 medium lemon
500 ml/ 17 fl.oz/ 2 cups water
1 teaspoon vanilla extract, optional
1. Place the cherries without pitting them in a large, heavy-bottomed pot. Add the sugar, lemon juice and water, stir and cook gently on medium heat until the sugar dissolves completely about 5 to 10 minutes.
2. Mash the cherries with a potato masher, add vanilla if using (or other spices). Continue simmering, stirring from time to time, until they are really soft, about 15 minutes.
3. Strain through a fine-mesh sieve and press the cherries with the back of a spoon to help them release all the juices. Pour the syrup into sterilized bottles. Keep refrigerated, it will keep for about 4 weeks.
4. If you want to keep it for longer, can the syrup in a water bath or in a canner for 10 minutes, adjusting for altitude. In this case, fill the syrup into smaller bottles or jars that will fit in the canner or canning pot. Leave to cool on a folded kitchen towel and store in a dark cool place, the canned syrup will last for about 1 year.