Set the mint ice cream on counter to thaw while you are making the cookie crust
Crush mint cookies in a food processor or by hand. If you crush them by hand, place them in a large Ziplock bag and crush with a rolling pin. Add melted butter to crushed cookies and mix well
Place crushed cookies on bottom of a lightly greased springform pan. (You can also use a 9x13 cake pan.)
Bake in a 350* oven for 7 minutes
Remove cookie crust from oven and let cool
Mix softened ice cream and Cool Whip in a large bowl
Spread ice cream mixture on top of cookie crust
Place in freezer for at least 5 hours or overnight, covered with foil