14- oz can low fat sweetened condensed milk
1/2 cup heavy cream
2 1/2 cups half and half
1 tablespoon vanilla extract
1/2 cup blackberry jam divided
Combine sweetened condensed milk, cream, and half and half in a large bowl. Add vanilla extract and 2 tablespoons of the jam to the milk mixture. Whisk until completely combined.
Pour milk/cream mixture into your ice cream maker.
Meanwhile, while ice cream is churning, heat the remaining jam in a small saucepan over medium heat until jam is thin and liquid-like. Drizzle the de-seeded, thinned jam into the ice cream maker five minutes before the churning is complete.
Transfer thickened ice cream to a freezable container and freeze overnight.