Combine the heavy cream, ¾ cup of the half & half, the simple syrup and the vanilla in a bowl. Whisk together and set aside.

In a saucepot, add the remaining half & half, chocolate chips and cocoa powder. Place over medium-high heat and bring to a simmer. Whisk continuously until the chocolate is completely melted and well-incorporated.

Combine both mixtures. Taste and adjust flavor if needed by adding more vanilla or simple syrup. Place in the refrigerator overnight to mature flavors.

Churn following machine manufacturer’s instructions until a creamy, thick, sticky consistency is achieved. Allow ice cream to harden 1 hour in the freezer before serving.