Oreo Pistachio Dessert

1 (15 ounce) bag Oreo cookies, rolled into crumbs
1/3 cup melted butter
1 small box pistachio Instant pudding
1 1/2 cups milk
1 quart vanilla ice cream, softened
1 (8 ounce) container Cool Whip

Mix Oreos and butter, divide. Spread 1/2 on bottom of 11 x 8-inch pan. Reserve other 1/2 of crumbs for top.

Prepare pudding, using the milk, according to directions on box.

Mix all remaining ingredients and pour over half cookie crumbs. Sprinkle remaining crumbs on top. Freeze.