Place 20 cookies in a gallon size resealable bag and begin crushing the cookies with a rolling pin or meat mallet until the cookies become coarse crumbs. Pour the cookie crumbs into a large bowl with the melted butter and toss to combine. Press into a greased 8 or 9-inch square baking dish, compacting them loosely in there. Set aside.

Wipe out the bowl and add in the pudding mix, mint extract and milk, whisking until combined and letting sit for 2 minutes. Add in one package (2 cups) of the Cool Whip, folding it in until combined. Carefully spread this mixture over the cookies in the pan.

Spread the remaining Cool Whip over the top of the chocolate mint pudding layer.

Crush the remaining cookies in another plastic bag until coarse crumbs as formed. Sprinkle the cookies over the top with the mint candy pieces. Cover and refrigerate for at least 6 hours before cutting into slices to serve.