What You’ll Need:
2 (4-serving-size) packages instant pistachio pudding and pie filling, prepared according to package directions
1 (8-ounce) container frozen whipped topping, thawed
1/4 cup plus 2 tablespoons coarsely chopped pistachios, divided
1 (14.4-ounce) package chocolate-flavored graham crackers
1 (16-ounce) container chocolate frosting
What To Do:
In a medium bowl, combine pudding mix, whipped topping, and 1/4 cup chopped pistachios. Place a single layer of graham crackers in bottom of a 9- x 13-inch baking dish. Top with one-third of pudding mixture.
Repeat layers of graham crackers and pudding 2 more times, ending with a layer of graham crackers.
Spread frosting over top, sprinkle with remaining chopped pistachios, then cover and chill overnight, allowing graham crackers to soften. Cut into squares and serve.
From: https://www.mrfood.com/Frozen-Dessert-Recipes/Pistachio-Icebox-Cake