Preheat oven to 160C (fan ovens) gas mark 4 or equivalent
You will need up to 18 paper cupcake set out in 2 x 12cup muffin tins (cupcake cases can vary in size slightly depending on brand.
Whiz butter and sugar together in the processor until creamed and fluffy. Add lemon zest just before the end and whiz in briefly.
Add raising agents to weighed flour.
Sieve some flour over the mix, add eggs then sieve remaining flour on top.
Whiz to combine. Add cordial and whiz until smooth and glossy.
(You will need to scrape the mixture down from the sides a couple of times with a flexible spatula.)
Divide mixture equally between paper cases: around a dessertspoonful for each case.
Bake for around 15-20 minutes until risen and golden and springy to touch: a skewer inserted should come out clean.
Leave to settle for a few moments then remove from tins and cool on a wire rack.
Once cakes are cool slice a circle from the top of each.
Spoon a little dollop of buttercream onto each cake. Cut each cut-off top in half to make wings and arrange on top of the buttercream.
Beat the butter until creamy in a roomy bowl. Add the icing sugar, a little at a time and stir vigorously to combine. Finally, stir in the lemon juice to loosen the mixture to spreadable consistency.
Alternatively, for even faster easier icing, whiz the butter and icing sugar together in the clean dry processor bowl. Add lemon juice through spout and whiz until smooth and glossy.