Directions

1. Set the bottom pan of a double boiler or bain marie over medium-low heat; add water to about a 2-inch depth. While the water heats to a bare simmer, put all the custard ingredients into the top pan and whisk until the mixture is completely combined and smooth. Set on top of the bottom pan.
2. Cook the custard, stirring almost constantly until the custard thickens and its temperature is 170° F on an instant-read or candy thermometer. Remove the pan of custard from the bottom/hot pan. (The custard will be a saucy consistency. If you have any suspicion that the custard has curdled, strain it into a bowl and proceed with the bowl of custard, ditching the pan.)
3. Sprinkle the bittersweet chocolate over the hot custard and stir to melt and mix it into the custard. Add the whiskey and stir it in.
4. Prepare an ice bath in a bowl that will accommodate the pan of custard; set the pan of custard into the ice bath. When the custard is cool to the touch (about 20 minutes), take the pan out of the ice bath. Dry the bottom of the pan and put it into the fridge to chill for at least 1 hour and up to overnight (cover, if overnight).
5. Pour the cold custard into an ice cream machine and process to soft-serve consistency. Scoop the ice cream into a quart container with a lid. Lay a piece of waxed paper or baking parchment directly onto the surface of the ice cream; put the lid on the container. Put the container into the freezer to ‘harden off’ the ice cream, at least 5 hours.

Alternate Vitamix or Blendtec method

1. If you have a super-powerful blender such as a Vitamix® or Blendtec,® the friction created by the machine’s high RPMs will heat and cook the custard — no stove time!
2. To make the custard in the one of these blenders, put all the custard ingredients into the jar of the blender and put the cover. Start the blender on low speed and gradually increase to high-speed. Let the machine run until the custard heat to 170˚ F on an instant-read thermometer, about 7 minutes. (Carefully insert the thermometer through the hold in the lid. Don’t let the custard get any hotter than 172° because the eggs will curdle.)
3. Put the chopped chocolate into a bowl, pour the hot custard over it and stir until the chocolate has completely melted and is combined into the custard. Stir in the whiskey.
4. Set the bowl of custard into an ice bath, then follow the recipe instructions above for chilling and freezing.