Step 1

Make the custard base: Combine the milk and heavy cream in a 3-quart saucepan. Using the tip of a sharp knife, split the vanilla bean and scrape the seeds into the milk mixture, then add the vanilla bean.

Step 2

Heat the milk mixture over medium heat, stirring occasionally, until small bubbles form and it starts to steam. This takes about 6 to 7 minutes.

Step 3

Meanwhile, in a medium bowl, combine the egg yolks and sugar. Whisk until the mixture is smooth and sugar is dissolved.

Step 4

Gently heat the egg mixture by slowly adding ½ cup of the warmed cream mixture to the egg mixture while continuously whisking. Add another ½ cup of the chocolate cream and temper the egg mixture again. This process is called tempering the eggs, and its purpose is to prevent the eggs from curdling while the custard cooks.

Step 5

Pour the warmed egg yolk mixture back into the saucepan with the remaining milk. Bring the mixture to a simmer over medium heat (don't let it boil). Cook until the custard has thickened, stirring constantly, about 4 to 6 minutes. It should coat the back of the spoon and leave a trail when you draw your finger through it.

Step 6

Strain the custard through a fine mesh strainer into a clean bowl, removing the spent vanilla bean. If the custard boiled during thickening, straining it out will help remove any curdled bits of egg. If you are using vanilla extract instead of a vanilla bean, stir it in now.

Step 7

Cool the base using an ice bath (½ ice cubes, ½ water, reaching halfway up the sides of the bowl). Stir the custard occasionally until it's cooled to room temperature (a digital thermometer should read about 80 °F).

Step 8

Place a piece of plastic wrap on the surface of the custard and refrigerate until chilled, at least 4 hours or overnight. Chilled custard can be kept in the refrigerator for several days. For the best results, make sure the base is about 40 °F prior to churning.

Step 9

Churn the ice cream: Pour the cold base into an ice cream maker and freeze per the manufacturer’s instructions, about 25 to 30 minutes. The finished ice cream will have a soft consistency.

Step 10

Ripen the ice cream: Transfer the ice cream to a freezer-safe container and smooth the top over using a small offset spatula. Freeze for 2 to 4 hours to allow the ice cream to firm up, a process called ripening. Serve and enjoy!