If you're a ginger fan, you'll love this sweet-hot combination of ambrosial white nectarines and ginger. Candied ginger purée is a handy condiment to have in your kitchen, and it's generally available in specialty stores. If you prefer, you can substitute chopped crystallized ginger - or if you really like ginger, use them both! Yellow nectarines or peaches can be substituted as desired; these aren't as sweet than white nectarines, so you may want to increase the sugar by 1/4 cup.
Place the water, sugar, and fresh ginger in a small saucepan and bring to a boil over high heat, stirring to dissolve the sugar. Remove from the heat and add the honey, stirring to blend. Let the mixture sit at room temperature for 30 minutes to allow the flavors to develop. Strain into a large bowl, pressing hard on the solids.
Add the lemon juice, nectarines and candied ginger purée, if using, stirring well to combine. Refrigerate the mixture, covered with plastic wrap, for 1 to 2 hours or until very cold.
Add the yogurt, stirring to blend. Freeze in an ice cream maker according to the manufacturer's instructions. About 5 minutes before the yogurt is set, add the crystallized ginger, if desired. Transfer to a clean container, cover and freeze until firm, about 2 hours.