To me, life would not be complete without chocolate hazelnut spread. This sandwich combines chocolate hazelnut ice cream and chocolate hazelnut cookies with the extra bonus of crunchy chopped hazelnuts around the edges. It’s absolute perfection.
Prepare an ice bath by filling a large bowl with ice cubes and 1 to 2 cups of water. Place a medium bowl fitted with a fine strainer inside the ice bath.
In a medium saucepan, combine the milk, cream, vanilla, sugar, and salt. Set over medium heat, stirring occasionally, until the mixture is warm and begins to steam, about 5 minutes.
In a medium bowl, whisk together the egg yolks until smooth. Carefully whisk 1/2 of the warm milk mixture into the egg yolks, 1 ladleful at a time, until the egg mixture is warmed. Whisk the egg-milk mixture back into the saucepan. Cook the mixture over medium heat, stirring constantly with wooden spoon, until the mixture is thick enough to coat the back of the spoon and registers around 175 degrees on an instant-read thermometer, about 5 to 7 minutes. Be careful not to boil the mixture.
Immediately strain the mixture through the fine strainer into the prepared ice bath. Stir in the chocolate hazelnut spread and mix for several minutes until dissolved. Don’t worry if the chocolate hazelnut spread does not dissolve completely. Cool the custard in the ice bath until it reaches room temperature, stirring often. Press plastic wrap against the surface of the custard and refrigerate until chilled, about 4 hours or up to 1 day.
Pour the chilled mixture into an ice cream maker. Freeze according to the manufacturer’s directions. Transfer the ice cream to an airtight container, press plastic wrap against the surface of the ice cream, and freeze until it is firm and the flavor is ripened, at least 2 hours.
Preheat the oven to 350 degrees. Line large baking sheets with parchment paper or silicone baking mats.
In a medium bowl, sift together the flour, cocoa powder, baking soda, and salt.
In large bowl, beat the butter and sugars on medium-high speed until smooth and well combined. Add the chocolate hazelnut spread and beat until combined. Add the egg, vanilla, and milk, and beat until combined. On low speed, gradually add the flour mixture and beat until combined. Cover the dough with plastic wrap and chill in the refrigerator for at least 15 minutes or up to 2 days.
Drop 2 tablespoon-sized balls of dough onto the prepared baking sheets. Bake for 10 to 12 minutes, or until the cookies are set. Remove the pans to wire racks to cool completely. Freeze the cookies until frozen, at least 1 hour. Cookies can be stored in airtight containers in the freezer for up to 1 month.
To assemble, top 1 cookie with a scoop of ice cream. Place another cookie on top of the ice cream and gently press down to form a sandwich. Roll the edges in the chopped hazelnuts and repeat for the remaining cookies. Freeze for at least 1 hour before serving.