Add the blueberries, sugar, lemon zest and lemon juice to the saucepan.

Bring to a boil over medium high heat.

Reduce heat to medium and cook, stirring occasionally,  15-20 minutes or until the mixture has thickened.

Remove from heat and allow to cool slightly. 

Add the mixture to a blender and blend until smooth. 

In the bowl of a stand mixer fitted with the whisk attachment, beat the heavy cream until stiff peaks form.

Fold in the sweetened condensed milk. 

Fold in the blueberry mixture. 

Freeze the mixture in your ice cream maker according to the manufacturer’s instructions. 

If you don't have an ice cream maker, transfer the chilled mixture to a lidded plastic container and freeze for minimum 4 hours or until set.