In the bowl of a stand mixer with the whisk attachment, whip the heavy cream until stiff peaks form and it thickens up to whipped cream.
Meanwhile, in a large bowl, mix together the condensed milk, ube jam, ube powder, and vanilla until combined.
Gently fold the whipped cream into the ube mixture until evenly combined and the color is evenly distributed.
Pour the mixture into the Ninja Creami pint cups, taking care not to go past the Max Fill line, and cover.
Freeze overnight or 24 hours.
Remove pint from the freezer and secure in the Ninja Creami according to package directions. Select Ice Cream mode and let it process until it stops, usually just about 2 minutes or so.
One the Ninja Creami has stopped, remove the outer bowl from the machine, remove the pint container from the bowl, and serve. Or, cover and freeze the ube ice cream for later.
Notes
Makes 2 pints (1 pint = 2 cups, which equals 4 servings)Ube jam: you can make your own, or buy ube jam at an Asian supermarket or online.Ube powder: you can buy ube powder online if you can't find it at your local Asian supermarket. Powder creates a lighter purple color. If you want a dark, brighter, bolder purple color, substitute ube extract for the powder.