crush cookies, combine with melted butter and press into 9x13 pan
Allow ice cream to soften (20 min). Spread over cookies. Freeze.
In double boiler - combine chocolate, butter, sugar, and evaporated milk. Sitr frequently until slightly thickened (about 15 minutes). Remove from heat and stir in vanilla. Set bowl in ice ciubes. Spread over ice cream. Freeze 30 min.
Spread cool whip on top. Freeze 2 hours.