In a small saucepan, combine the heavy cream and whole milk. Heat gently over medium heat until just simmering.

In a mixing bowl, whisk together the egg yolks and granulated sugar until light and fluffy.

Slowly add a small amount of the hot cream mixture to the egg yolks, whisking constantly.

Pour the tempered egg mixture back into the saucepan with the remaining cream. Stir continuously over low heat until thickened.

Remove from heat and stir in vanilla extract.

Transfer custard to a bowl and let it cool to room temperature.

Cover and refrigerate for at least two hours.

Pour custard into the Ninja Creami container and process according to the manufacturer's instructions.