Always smell the peaches before you buy them to make sure they are sweet and ready to eat.
1 1/2 cups water
2/3 cup sugar
2 tbsp light corn syrup
1 lb fresh peaches or nectarines, halved and pitted
1 tsp freshly grated lime zest
6 tsp lime juice
1/4 tsp salt
Stir water, sugar and corn syrup in a large saucepan over medium heat until the sugar dissolves. Add peaches or the nectarines; bring to a simmer. Reduce heat, cover and simmer for 10 mins.
Pour the mixture into a blender. Add lime zest, juice and salt; blend until smooth. Pour into a large bowl and refrigerate until cold, 4 hours or overnight.
You can also pour the mixture into ice cube trays and freeze until solid.