Serves: 12 cakes1) Preheat the oven to 180C/Gas 4. Line the cups of a 12-cup standard-size cupcake tin with paper baking cases.
2) Combine the butter, brown sugar and granulated sugar in the bowl of an electric stand mixer fitted with the paddle attachment. Cream on medium-high speed until the mixture is light and fluffy, about 5 minutes. Scrape down the bowl and add the egg and banana puree. Cream for an additional 3 minutes.
3) Scrape down the bowl, and then add the flour, baking powder, bicarbonate of soda, cinnamon and salt. Mix for 30 seconds on low speed. Add the toffee pieces and buttermilk. Stir on low speed until combined.
4) Fill the prepared paper cake cases liners three-quarters full with batter and bake until golden brown and baked through, about 25 minutes. Cool the cupcakes completely on a rack.
For the dulce de leche toffee filling:
1) Stir the dulce de leche and toffee pieces together until fully combined.
2) Place in a pastry bag with a round tip large enough to allow the toffee bits to pass through without becoming lodged.
For the caramel cream cheese icing:
1) In the bowl of an electric mixer fitted with a paddle, beat the butter on medium-high speed until light and fluffy. Add the cream cheese and mix on medium-high speed until well combined and lump free. Scrape down the sides of the mixer bowl and add the icing sugar. Stir on low speed until well combined.
2) Add the vanilla essence and beat on medium-high speed for 2 minutes. Remove from the mixer and stir in the dulce de leche in by hand to create a marbled appearance. Place in a pastry bag fitted with a large round tip.
To assemble the cakes:
1) Using an apple corer, remove the centre core of the cupcakes and fill with dulce de leche toffee filling. Pipe the caramel cream cheese Icing generously on top of each cupcake.
2) Using a paring knife, gently poke the freeze-dried ice cream to create separated chunks. Place 4 chunks on top of each cupcake. Dredge the outer rim of each cupcake in the chocolate granules.