Whoopie pies prove that (spicy, treacley) cake really is just a vessel for the (zesty, sherbety) frosting.
Based on Ginger Lemon Cream Sandwich Cookies by Portuguese Girl Cooks.
NB: These are the tall, muffin-like version of whoopie pie, rather than the black-and-white-cookie–like variety.
2 + 1/4 cups plain flour
1 tsp baking powder
1/4 tsp salt
1 tsp ground ginger
1 tsp cinnamon
1/2 tsp cloves
1/4 tsp nutmeg
165 g butter (room temp.)
1 cup dark brown sugar
1 tsp vanilla
1/4 cup treacle (or golden syrup)*
For the frosting:
zest and juice of one lemon
5 chunks of crystallised ginger
85 g cream cheese (room temp.)
55 g butter (room temp.)
2 + 1/2 cups icing mixture
- Preheat the oven to 190° C.
- In a medium bowl, sift together the flour, baking soda, salt and spices.
- If the butter is still cold, soften slightly in the microwave (10 seconds at most).
- In the bowl of a stand mixer with the paddle attachment (or a large bowl with hand beaters), cream together the butter and sugar (about 3–4 minutes).
- Add the egg, vanilla and treacle/golden syrup, beating til combined.
- Slow down the mixer, carefully add the flour mixture, and mix until just combined.
- Scoop out heaped tablespoons of mixture onto a baking sheet.** Bake each batch for about 8 minutes, or until the surface is dry and the edges are golden.
- Leave to rest on a cooling rack until the cake/cookie halves are at room temperature.***
- For the frosting: Finely chop/mince the crystallised ginger; zest and juice the lemon. You can set these aside in the same bowl until needed.
- Sift the icing mixture into a medium-sized bowl. Set aside.
- In the bowl of a stand mixer with the paddle attachment (or a medium-sized bowl with hand beaters), beat together the cream cheese and butter at high speed, until glossy and fully combined.
- On slow speed, carefully add the icing mixture.
- Remove from the stand mixer and/or switch to a wooden spoon; stir in the lemon and ginger.
- Allow to sit for 15 minutes or so until the frosting is solid enough to act as an edible cement.
- To assemble: Pick out pairs of similarly sized cake/cookie halves, and sandwich together with a heaped teaspoon or so of frosting. If the frosting isn’t solid enough, add a bit more sifted icing mixture.
You can leave out the crystallised ginger in the frosting if you’re baking for an anti–crystallised ginger audience. You can also so some preliminary research on Wikipedia if that same audience wants to know about the history/etymology of the whoopie pie.
It’s easier to transport these unassembled. If you’re planning to do so, put the cake/cookie halves in an airtight container at room temperature once they’re fully cooled, and store the frosting in an airtight container in the fridge until you’re ready to go. Take the frosting out of the fridge about half an hour before assembling, so it’s pliable but still firm enough to cement the two cake/cookie halves together.
*Treacle for a dark, spicy flavour; golden syrup to keep it super-sweet. Either way, put a bit of olive oil in the measuring spoon beforehand so it doesn’t stick!
**Now’s the time to use a cookie scoop if you have one. Ideally, you want matching, all-the-same size, circle-shaped halves.
***If you want flatter halves, leave them to cool top-side down.