Combine cream, vanilla and Maxigenes premade milk in a large saucepan over medium heat and bring to a simmer.
Use a mixer to beat egg yolks and 1 cup of sugar until thickened and pale. Slowly add the cream mixture, in batches until well combined.
Pour the mixture into a clean saucepan on low heat. Continue stirring for approximately 10 minutes or until mixture coats the back of a spoon. Set aside to cool.
Por mixture into a metal container and cover with foil. Place in freezer for 3 hours.
Combine blueberries and the extra caster sugar in a saucepan over medium heat. Continue stirring for about 5 minutes or until mixture thickens. Set aside to cool.
Roughly break up ice cream with a spoon. Transfer the ice cream into a food processor and process till smooth. Add half the mixture to the metal container and add half the blueberry mixture. Gently swirl through.
Repeat with ice cream and blueberries. Cover with foil and freeze for 3 hours.