Line an 8x8-inch baking pan with parchment paper, leaving enough overhang on the sides to easily lift the frozen bars from the pan.

Place 12 Biscoff cookies in an even layer across the bottom of the prepared pan.

Add the cold heavy whipping cream to a large mixing bowl. Using an electric mixer, beat until stiff peaks form. Set aside.

In a separate large bowl, mix the sweetened condensed milk, vanilla bean paste, pinch of salt, and 2 tablespoons of Biscoff cookie butter until smooth and fully combined.

Gently fold the whipped heavy cream into the sweetened condensed milk mixture until mostly combined.

Add the thawed Cool Whip and gently fold until the filling is smooth, fluffy, and no streaks remain.

Spread half of the ice cream filling evenly over the bottom layer of Biscoff cookies.

Warm the remaining 2 tablespoons of Biscoff cookie butter for a few seconds, just until pourable. Drizzle it over the filling and gently swirl it through with the tip of a knife.

Spread the remaining ice cream filling evenly over the cookie butter swirl.

Arrange the remaining 12 Biscoff cookies over the top, matching their placement with the bottom cookies as closely as possible.

Cover the pan tightly and freeze for at least 6 hours, preferably overnight.

Remove the bars from the freezer and let them sit at room temperature for about 10 minutes. Lift from the pan using the parchment paper, slice into 12 bars using the top cookies as your guide, and serve immediately. Wrap any leftovers and place in freezer.