1. Process peanut butter crackers to crumbs and mix with margarine. Add to the bottom of individual dessert dishes.
2. Combine white chocolate and peanut butter in a microwave-safe bowl. Microwave on 15-seconds intervals, stirring in between, until smooth. Pipe this layer on top of cracker crumbs.
3. Add milk chocolate and peanut butter to a ceramic, glass or metal bowl. Heat heavy cream just until boiling. Pour over chocolate. Let sit a couple minutes, then stir until smooth. Stir in Rice Krispies. Pipe this layer over peanut butter layer. Keep frozen until day of serving, but serve at room temperature so it’s creamy and not hard.