Combine first 8 ingredients in a food processor. Process until smooth; scrape sides of bowl occasionally.
Pour mixture into the freezer can of an ice-cream freezer; freeze according to manufacturer's instructions. Spoon ice cream into a freezer-safe container; cover and freeze 1 hour or until firm. Garnish with lemon rind strips, if desired.
Note: Crystallized ginger can be found with the spices in the supermarket. If you're not a fan of ginger, omit it. We tested the recipe without the ginger and got a nice lemon taste.