3. Add half each of banana, sour cream and sifted dry ingredients, stir until just combined and then add remaining half and mix until just combined.
4. Place mix into a piping bag with a round nozzle. Pipe mix on to baking trays, approx. 4cm in diameter; leave a 4-5cm space between each one.
5. Bake for 10 minutes, preferably swapping baking tray positions after 5 minutes.
6. Remove from oven and transfer to cooling racks.
7. To make Caramel Creme, place cream cheese into a bowl and use an electric beater to whisk until soft and smooth. Add butter, vanilla and icing sugar and beat until combined. Take the caramel and swirl through lightly, ensuring it isn't completely mixed and has a nice swirled effect.
8. Mix the cinnamon and sugar together and place in a small flat dish or saucer.
9. To assemble, place half of the whoopie pies flat side up on the bench. Using a piping bag pipe the Caramel Creme filling to cover flat surface, leaving a 5mm edge around the rim uncovered. Sandwich this with another whoopee pie, and then roll the rim in the cinnamon sugar.