Place the rhubarb, sugar, and lemon juice in a small sauce pan, stirring frequenly, cook over medium-high heat until the rhubarb is tender and falling apart, about 8-10 minutes. Stir in the vanilla extract. Refrigerate the stewed rhubarb for at least 1 hour, stirring once.
When the stewed rhubarb has chilled, stir it into the sweetened condensed milk in a large bowl.
In a deep, chilled bowl, beat the heavy whipping cream until stiff peaks form.
Stir about one cup of the whipped cream into the rhubarb mixture. This will help lighten it, and make it easier to fold in the remaining whipped cream.
Scrape the mixture into a plastic container, cover with a lid, and freeze overnight.
Scoop and enjoy!
Recipe by Faithfully Gluten Free at http://www.faithfullyglutenfree.com/2014/07/no-churn-rhubarb-ice-cream.html