Step 1

Prepare an immersion circulator for use according to the manufacturer’s instructions. Preheat the water to 185°F (85°C).

Step 2

In a blender, combine the chocolate, vanilla seeds, milk, cream, sugar, cocoa powder, egg yolks, cinnamon, cayenne and salt and process on high speed until thoroughly mixed and smooth, about 2 minutes. Pour the custard into a sealable plastic freezer bag. Seal the bag closed except for a small opening at one corner. Holding the bag near the opening, slowly lower it into the water, leaving only the seal exposed. The pressure created by the water will force out the air, creating a substantial vacuum. Seal the opening securely closed. (Be sure to use a locktop bag, not one with a sliding closure, which does not allow a complete seal.)

Step 3

When the water reaches 185°F, lower the bag into the water bath and clip the top of the bag to the side of the water basin. Cook for at least 45 minutes and up to 1 1/2 hours. When the custard is ready, remove the bag from the water bath. You can either immerse the bag in a large ice-water bath until well chilled or refrigerate the custard in the bag overnight.

Step 4

Transfer the contents of the bag to an ice cream maker and freeze according to the manufacturer’s instructions. Serve the ice cream immediately, or transfer to an airtight container and place in the freezer for up to 1 month.

Step 5

To serve, spoon into individual bowls and garnish with the shaved chocolate. Makes 1 quart (1 l).

Step 6

Adapted from Williams Sonoma The Sous Vide Cookbook (Weldon Owen 2017)