Photograph: Ria Osborne
Preheat the oven to 180°C, fan 160°C, gas 4. Line a 12-hole cupcake tray with gold or silver foil cupcake cases.
Sieve the flour, baking powder and cornflour into a large bowl. Stir in the orange zest.
In a separate bowl, using an electric whisk, cream the soft butter and caster sugar together until light and fluffy. Alternately whisk in the beaten eggs and the flour mixture until combined. Fold in the lightly crushed fruit.
Divide the mixture evenly among the cupcake cases. Bake in the oven for 25 minutes.
While the cupcakes are baking, make the syrup. Gently heat the Pimm's with the sugar in a medium saucepan, stirring until the sugar has dissolved. Increase the heat and let it bubble for 5-7 minutes until thick and syrupy. Pour the syrup into a small jug.
As soon as the cupcakes come out of the oven, prick the tops a few times with a toothpick and brush them with the Pimm's syrup. Leave to cool in the tray for 10 minutes, then transfer to a wire rack and leave to cool completely.
While the cupcakes are cooling, make the buttercream. Using an electric whisk, mix together the butter, milk and Pimm's in a medium bowl until smooth. On a low speed, gradually add the icing sugar and continue to beat until smooth and thick. Transfer to a piping bag fitted with a 1cm star nozzle.
Once the cupcakes are completely cool, generously pipe each one with the icing, then decorate with sliced strawberries, orange slices, raspberries and the baby mint leaves.
Chef's tip: make the cupcakes a day ahead and ice before serving. The uniced cupcakes can be frozen.