Make crust: Preheat oven to 350. In food processor, process cookies til crumbs form. Add butter; pulse til mixture holds together when squeezed. Lightly butter an 8 inch square baking pan. Line it with two crisscrossed rectangles of parchment that hang out of pan on each side by a few inches. Press crust firmly into bottom of pan on top of parchment and slightly up the sides. Use the bottom of a metal measuring cup or small bowl to help pat crumbs in evnenly.
Bake until crust is firm and dry to the touch, 15- 20 minute Cool to room temperature.
Make filling: In clean food processor, process cream cheese, sugar, heavy cream, peanut butter, and salt until smooth and light, scraping sides as needed.
Peel bananas; halve lengthwise. Spread half the cream cheese mixture over the crust; top with a snug layer of bananas. Cover with remaining cream cheese mixture, smoothing top. Sprinkle with peanuts; cover with plastic wrap. Freeze til firm, at least 6 hours.
To remove, wipe outside 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.