Heat your oven to 180C/160C fan-forced and line a cupcake tin with 12 large patty pans.
With a stand mixer – beat the butter with the caster sugar until light and fluffy – combine the eggs and self-raising flour with the butter/sugar mix until well combined.
Add Australian Garden Gin, and Fever-Tree Tonic, and then beat again. The mixture will be runnier than usual which is why there is more flour added in.
Spoon the mix into the patty pans evenly and bake in the oven for 18-20 minutes or until a skewer poked into one of the cakes comes out clean and they are springy to touch – leave them to cool fully on a wire rack.
To make the Gin Syrup, add the sugar, Australian Garden Gin and Fever-Tree Tonic to a pan on boil for a minute so the sugar dissolves. Brush or spoon over the baked cupcakes.
For the buttercream, beat the butter with an electric mixer for a couple of minutes to loosen it – gradually beat in the icing sugar until well combined (this can take up to 5 minutes).
Add in the Australian Garden Gin and Fever-Tree Tonic one tablespoon of each at a time, and beat fully each time. The mixture will be slightly slacker than usual, if needed add more icing sugar to stiffen mixture.
Pipe on your buttercream icing, add a lime wedge, part of a straw (cutting a straw into thirds should give you the right size) and for some added garnish sprinkle with some lime zest and a mint leaf.