Directions

1. 1

   Pour the half-and-half and heavy cream into a medium saucepan. Place over medium heat and warm until small bubbles appear around the edges and steam rises from the surface, stirring occasionally. Do not allow it to boil.

2. 2

   Remove the saucepan from heat. In a separate medium mixing bowl, whisk the egg yolks vigorously until they become pale and slightly thickened, about 2–3 minutes. Gradually whisk in the sugar until well combined.

3. 3

   Slowly add the warm cream mixture to the egg yolk mixture in small amounts, whisking constantly. Start with about 1/3 of the cream and whisk thoroughly before each addition. This gradual tempering prevents the eggs from cooking.

4. 4

   Pour the combined egg and cream mixture back into the saucepan with the remaining cream. Place over low heat and stir constantly until the custard thickens enough to coat the back of a spoon and reaches 175°F on an instant-read thermometer. This will occur quickly; watch carefully.

5. 5

   Remove the custard from heat and let it cool to room temperature for about 30 minutes, stirring occasionally. Once cool, stir in the cola syrup until fully combined. Transfer to a covered container and refrigerate for at least 4 hours until completely cold.

6. 6

   Pour the chilled custard mixture into your ice cream maker and churn according to the manufacturer's instructions, typically until the mixture reaches a soft-serve consistency.

7. 7

   Transfer the ice cream to a freezer-safe container and freeze for 3–4 hours until firm. Serve and enjoy.