In a small saucepan on low heat cook the 1/2 cup water, 1/2 cup sugar and the chopped rhubarb until the rhubarb is soft.
Let cool.
Pour into a small bowl, cover and refrigerate
In a medium bowl beat 1 cup sugar and the cream cheese with a hand mixer.
Add the 2 eggs and vanilla and beat until smooth.
In a medium saucepan heat the milk until hot, but not boiling.
Remove from stove.
Slowly pour the hot milk into the cream cheese mixture and whisk until combined and smooth.
Return the custard to the saucepan and cook on low heat until the custard starts to thicken.
Stir occasionally.
Remove from heat and pour custard into a medium bowl to cool.
Once cooled whisk in the whipping cream and the lemon zest until smooth.
Cover the custard and refrigerate for at least an hour or overnight.
Pour cooled custard into your ice cream maker and follow ice cream makers instructions.
Once ice cream is finished, spoon ice cream into a glass rectangular dish.
Remove rhubarb from fridge and swirl the stewed rhubarb into the ice cream.
Optional
Swirl a couple Tbsp of gluten free graham cracker crumbs into the ice cream.
Cover and freeze until firm.