1. Make the crust: Preheat oven to 350 degrees. In a food processor, process cookies until crumbs form. Add butter; pulse until mixture holds together when squeezed. Prepare crust as directed below. Bake until crust is firm and dry to the touch, 15 to 20 minutes. Cool to room temperature.

2. Make the filling: In a clean food processor, process cream cheese, sugar, heavy cream, peanut butter, and salt until smooth and light, scraping sides of bowl as needed.

3. Peel bananas; halve lengthwise. Spread half the cream-cheese mixture over crust; top with a snug layer of bananas. Cover with remaining cream-cheese mixture, smoothing top. Sprinkle with peanuts; cover with plastic wrap. Freeze until firm, at least 6 hours.

4. To remove, wipe outsides of pan with a hot towel; run a knife around inside edge (between paper and pan). Gently pull on paper to lift out of pan. Cut into 12 rectangles.

5. Make the crust: Butter an 8-inch square baking pan. Line it with 2 crisscrossed rectangles of parchment paper. Press crust firmly into bottom and slightly up sides. Use the bottom of a measuring cup or small bowl to help pat crumbs in evenly.