Preheat oven to 150 degrees C. Grease a 26 cm round spring form tin; line base and side with baking paper. Combine the biscuit crumbs and butter in a bowl; mix well. Press over base or prepared tin. Refrigerate while preparing filling.
Beat cream cheese and sugar in a large bowl with an electric mixer until smooth. Add bananas; beat until combined. Add eggs; beat until combined. Pour into prepared crust. Cook cheesecake for about 75 minutes or until firm to touch.
To make the sour cream topping; combine all ingredients in a bowl.
When cheesecake is cooked spread the sour cream topping over it, then return cheesecake to oven, cook for 20 minutes or until topping is set. Cool in pan on a wire rack; refrigerate until cold. Serve with whipped cream and extra banana slices.