In a small saucepan, combine the blueberries, sugar, and lemon juice. Stir well and cook over low to medium heat for 5–7 minutes, or until the blueberries have softened and begin to burst.

Remove the saucepan from the heat and let the mixture cool for about 5 minutes. Mash the blueberries with a potato masher for a chunkier ice cream, or blend with an immersion blender for a smooth consistency. Allow the blueberry mixture to cool completely.

In a medium mixing bowl, whip the cold heavy whipping cream until stiff peaks form. Be careful not to overwhip, as the cream can become grainy.

In a separate bowl, whisk together the sweetened condensed milk, vanilla extract, and a pinch of salt until smooth. The salt helps enhance the sweetness and flavor.

Stir the cooled blueberry mixture into the condensed milk mixture until fully combined, making sure there are no lumps remaining.

Gently fold the whipped cream into the blueberry mixture a few spoonfuls at a time until everything is just combined. For a marbled look, avoid overmixing so some blueberry streaks remain visible.

Transfer the mixture to a loaf pan or freezer-safe container. Cover and freeze for at least 8 hours, or overnight, until firm.

Scoop into bowls or cones and enjoy your homemade blueberry ice cream!