Summary: This recipe was adapted by Redwood Hill Farm from the Bon Appetit’s Lemon-Buttermilk Sorbet, June 2001. They’ve replaced the buttermilk in the original recipes with an equal amount of their plain kefir. Meyer lemons give this a distinctive taste but standard lemons can be used if Meyers are not available. This sherbet can be made up to 3 days ahead. Keep frozen.