- 2 cups heavy cream
- 2/3 cup prepared chocolate syrup
- 1 teaspoon peppermint extract
- 16 (4-ounce) ice cream sandwiches, divided
- 1 cup finely chopped mint-and-fudge cookies, such as Keebler Grasshopper cookies (about 10 cookies), divided
- Using an electric mixer on medium-low speed, beat cream in a large bowl until medium-stiff peaks form. Gently fold in chocolate syrup and peppermint extract. Transfer half of the cream mixture to a medium bowl; cover and chill until ready to use.
- Spread a thin layer of remaining cream mixture on bottom of a platter. Top with 4 ice cream sandwiches, placing 3 side by side and 1 along bottom of row for a square-shaped base, or 4 side by side for a rectangular-shaped base. Top with a thin layer of cream mixture and sprinkle with 1/4 cup cookies. Continue layering sandwiches, cream, and cookies, ending with a layer of cream, until all sandwiches are used (you should have 4 layers; reserve remaining 1/4 cup cookies). Wipe any excess cream off platter, then freeze until set, at least 1 hour or up to overnight.
- Using a spatula, frost top and sides of cake with reserved cream mixture. Sprinkle reserved 1/4 cup cookies over cake. Freeze again 30 minutes, then slice and serve.
- Fully assembled cake can be made 1 day ahead; keep frozen.