01 - In a large mixing bowl, beat the cold heavy whipping cream using an electric mixer on medium-high speed until stiff peaks form, approximately 2 to 3 minutes.
02 - Gently fold the sweetened condensed milk, vanilla extract, and melted Biscoff spread into the whipped cream using a spatula. Work with light sweeping motions to preserve the airy texture until the mixture is uniformly combined and smooth.
03 - Transfer the mixture into a loaf pan lined with parchment paper. Smooth the surface with a spatula, cover tightly with plastic wrap, and freeze for at least 4 hours or until completely firm.
04 - Remove the ice cream from the freezer and let it rest at room temperature for about 5 minutes to soften slightly for easier scooping.
05 - Arrange 8 Biscoff cookies flat side up on a chilled baking sheet. Scoop approximately 1/4 cup of the semi-firm ice cream onto each cookie, then press a second cookie on top. Apply gentle, even pressure to form a neat sandwich.
06 - If desired, roll the exposed edges of each sandwich in crushed Biscoff cookies. Return all assembled sandwiches to the freezer for 10 to 15 minutes to firm up before serving.