2 cups fat-free milk
1/4 cup arrowroot powder
1 1/3 cups Naturally Sweet Xylitol
4 egg yolks
2 1/2 teaspoons vanilla extract
1 cup reduced-fat sour cream
1 cup whipping cream
Place milk in a small saucepan and heat to almost boiling. Remove from heat and set aside. Combine arrowroot powder and Naturally Sweet Xylitol in a medium bowl. Thoroughly beat egg yolks into xylitol mixture. Slowly add scalded milk to egg mixture, stirring until well blended. Transfer this mixture to top of double boiler, and cook over boiling water, stirring constantly, until custard is thick and smooth. Strain, if necessary. Stir in vanilla extract, and pour mixture into a large bowl. Stir in sour cream until thoroughly combined, cover bowl, and refrigerate until chilled.
Beat whipping cream until soft peaks form. Gently fold whipped cream into chilled custard mixture. Transfer to small automatic ice cream maker and freeze.