Method

1. Preheat oven to 180°C. Line a 12-hole, ⅓-cup (80ml) muffin pan with paper cases.
2. Use an electric mixer to beat the butter, sugar and lemon rind in a bowl until pale and creamy. Add the eggs, 1 at a time, beating well after each addition. Add flour and stir to combine. Add the sour cream and lemon juice and stir to combine. Add the lemon curd and gently fold to marble.
3. Divide mixture evenly among the paper cases. Bake for 20-25 mins or until a skewer inserted in the centres comes out clean. Set aside to cool.
4. To make the pink cordial buttercream, use an electric mixer to beat the butter in a bowl until very pale. Gradually add the icing sugar, in batches, beating well after each addition. Add the cordial and beat until well combined.
5. Spoon the buttercream into a piping bag fitted with a 1cm fluted nozzle. Pipe over cupcakes. Drizzle with extra cordial and top with lemon slices.