Homemade Speculoos Ice Cream

Ingredients

• 5 1/2 ounces Toasted Sugar
• 4 ounces egg yolk, from about 8 large eggs
• 3/4 teaspoon Diamond Crystal kosher salt, plus more as needed; for table salt, use half as much by volume or use the same weight
• 1/8 teaspoon baking soda
• 6 3/4 ounces Biscoff crumbs, from store-bought or homemade cookies
• 9 ounces heavy cream
• 11 ounces whole milk
• 1/4 ounce bourbon or rye whiskey, or whatever sounds tasty, optional
• 1 teaspoon vanilla extract

Directions

1. In a 3-quart stainless steel saucier, whisk together the toasted sugar, egg yolks, salt, and baking soda. Add the cookie crumbs, cream, and milk, whisking until combined. Set the pan over medium-low heat and warm the mixture for a few minutes, just until it feels warm.
2. Turn the heat up to medium. Cook the custard, stirring steadily and scraping the pan with a flexible spatula, until it is very hot and steamy, about 8 minutes or 155 degrees F (68 degrees C). Strain it into a large stainless steel bowl through a fine-mesh sieve, using a flexible spatula to lightly press the crumbs so the custard caught inside can drain out.
3. Add a few inches of ice water to a sink compartment or extra-large bowl, then nestle the bowl of custard inside. Stir occasionally until the custard has cooled, about 30 minutes. Cover the bowl and chill until the base is no warmer than 40 degrees F (4 degrees C), about 4 hours. The base can stay in the refrigerator for up to 1 week.
4. Mix in the whiskey and vanilla, then taste and add more salt if you’d like. Freeze the custard in an ice cream machine, following the manufacturer’s instructions. While it churns, put a 1-quart container and a flexible spatula in the freezer.
5. Once the ice cream is pale, thick, and fluffy-looking, stop the machine. Transfer it to the cold container with the chilled spatula. You can eat it right away as soft-serve, or press plastic directly onto the ice cream, cover with the lid, and freeze until firm, about 4 hours.