01 - In a large mixing bowl, beat the heavy whipping cream using an electric mixer on medium-high speed until stiff peaks hold their shape, approximately 2 to 3 minutes. Be careful not to over-whip.
02 - Gently fold the sweetened condensed milk, vanilla extract, and melted Biscoff cookie butter into the whipped cream using a rubber spatula. Work in slow, 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, spreading it into an even layer. Smooth the surface with your spatula, then cover tightly with plastic wrap. Freeze for a minimum of 4 hours, or until the ice cream is completely firm throughout.
04 - Remove the ice cream from the freezer and let it rest at room temperature for about 5 minutes so it softens slightly, making it easier to scoop without breaking the cookies.
05 - Arrange 8 Biscoff cookies flat side up on a parchment-lined baking sheet. Using an ice cream scoop, portion approximately 1/4 cup of ice cream onto the center of each cookie. Press a second cookie gently on top, applying even downward pressure until the ice cream spreads to the edges and forms a neat sandwich.
06 - If desired, roll the exposed ice cream edges of each sandwich in the crushed Biscoff cookies, pressing lightly so the crumbs adhere evenly around the perimeter.
07 - Return the assembled sandwiches to the freezer for 10 to 15 minutes to firm up before serving. Once set, they are ready to enjoy. Store any leftovers wrapped individually in parchment paper inside an airtight container in the freezer for up to one week.