Line an 8-inch square pan with foil, extending it over the edges of the pan.
Lightly grease the pan.
In a large microwave-safe bowl, combine the frosting, white chocolate chips, and butter.
Microwave on high for 2 minutes, stir, then continue microwaving at 30-second intervals until the chips are completely melted and smooth.
Stir in vanilla.
Fold in the crushed Biscoff cookies until just blended.
Spread evenly into the prepared pan.
Allow to set at room temperature for about a half hour, or for 10-15 minutes in the refrigerator.
Remove from pan by lifting the edges of the foil. Remove the foil.
Cut into squares, and DEVOUR!