Let me start this post by saying that these whoopie pies are the monsters of the whoopie pie world – I think I got a little carried away when spooning the sticky mixture onto the baking trays! That’s not to say they’re not delicious, they really are gorgeous, but just to say that you might want to share one with a friend (or make yours smaller, but I like the sharing thing better!) You could maybe make 10 pies instead of the 7 that I got out of the mixture, but either way they’re definitely worth giving a go! I halved the filling mixture that was originally set out in the recipe, as I find that generally these cookbooks way over-estimate the amount of filling that goes in these things, but if you want to double the amount then that’s good too! And who on this earth does not simply love a whoopie pie? I have yet to find someone who does not, maybe those kinds of crazy people are on another planet or something. Anyway, the recipe is from The Hummingbird Bakery.
For the Sponge
1 large egg
150g (5½oz) caster sugar
125g (4½oz) plain yoghurt
25ml (1floz) whole milk
¼ tsp vanilla essence
75g (2½oz) melted unsalted butter
275g (10oz) plain flour
¾ tsp bicarbonate of soda
¼ tsp baking powder
150g (5½ oz) chocolate chips
75g (3oz) unsalted butter
2 tbsp cocoa powder
140g (5oz) icing sugar
110g (4oz) vanilla marshmallow fluff
Using a hand-held or freestanding mixer, cream the egg and sugar until pale and fluffy. Pour the yoghurt, milk and vanilla essence into a jug and stir together then add to the beaten egg and sugar. Add the melted butter and mix in thoroughly on a medium speed.
Sift the remaining sponge ingredients together, then add to the creamed mixture in two batches, mixing well on a medium speed after each addition. Place the batter in the fridge to cool and set for 20-30 minutes.
Meanwhile, preheat the oven to 170C, (325F) and line two baking trays with baking parchment or grease whoopie pie trays.
Once the batter has cooled down, spoon it on to the prepared trays, dividing the mixture into 16-20 rounds (8-10 per tray), each 3-5 cm in diameter and spaced 2-3cm apart.
Bake in the oven for 10-13 minutes or until springy to touch. Remove from the trays and place on a wire rack, allowing them to cool completely before sandwiching together.
While the sponges are cooking, make the filling. Using the electric whisk or freestanding mixer with the paddle attachment, mix together the butter and the icing sugar on a low-speed until well blended. Add the marshmallow fluff, and lightly mix it in, then increase the speed to high and continue mixing until light and fluffy. Place in the fridge and leave for about 30 minutes to firm up slightly.
To assemble the whoopie pies, take one of the sponges and spread about 1 tablespoon of the filling over the flat side, adding a little more if needed. Then stick another sponge, with the flat side facing down, on the filling to make a sandwich. Repeat with the remaining sponges and filling.