Place sandwich cookies in the bowl of a food processor. Pulse those suckers until coarse crumbs begin to form. (Don't over-process here; you want a mix of large and small cookie pieces). Transfer cookie crumbs to a large bowl. Add fudge topping to the bowl and stir until combined.

Line an 8-inch square baking pan with wax or parchment paper, allowing the edges of the paper to extend over sides of the pan. Firmly press 1/2 of the cookie mixture into an even layer in the bottom of the pan. Place another layer of wax or parchment paper over the cookie layer. Press the remaining 1/2 of the cookie mixture into an even layer over the paper on top of the first cookie layer. Place another layer of wax or parchment paper over second cookie layer to cover; press firmly to adhere. Freeze for at least 3 hours.

Lift the sides of the second layer of wax paper to remove the top cookie layer from pan; set it aside for the moment. Spread softened ice cream in an even layer over bottom cookie layer in the pan using a rubber spatula. Peel away both layers of paper from the top cookie layer and gently place on top of the ice cream layer, giving it a firm press. Freeze for 4 hours or until the ice cream is firm.

Slice the big sandwich thing into 9 bars and serve immediately, returning any remaining sandwiches to the freezer. Sandwiches can be individually-wrapped in plastic wrap and kept in the freezer for up to 10 days.