Add bananas to food processor and blend. When the bananas start to become smooth and close to the consistency of soft serve, add the peanut butter. Process until smooth.
Pour into an 8-inch springform pan and smooth over the top. Freeze for at least one hour or overnight.
Topping: Take out the cake. Run the edges briefly under hot water to help remove the ring of the springform. Melt the chocolate chips in the microwave for about 40 seconds and drizzle over top of the cake. Sprinkle on crushed peanuts. Place the cake back in the freezer for about 5 minutes to harden the chocolate.
Remove from freezer for 5-10 minutes to soften it before serving. A knife dipped in warm water helps the slicing process.