Ingredients

Step by step

1. Preheat the oven to 190°C, fan 170°C, gas 5. Line a 12-hole muffin tin with paper muffin cases.
2. Finely grate the zest of 1 of the lemons. Whisk the butter and sugar in a bowl with an electric hand whisk or beat with a wooden spoon until pale and creamy. Gradually whisk in the eggs until just combined, then add the flour and milk. Whisk with an electric hand whisk until combined and fluffy, then fold in the lemon zest.
3. Divide equally between the paper cases and bake in the oven for 20-25 minutes or until the cakes are golden and risen. Leave in the tin for 5 minutes, then transfer to a wire rack to cool.
    
4. Meanwhile, slice 12 small slices from the ends of the remaining 3 lemons. Then squeeze the juice from all 4 lemons – you'll need 75ml lemon juice.
5. Put 100ml cold water into a pan and bring to the boil. Add the lemon slices and cook for 7-8 minutes until beginning to soften. Add the lemon juice and caster sugar and heat until dissolved. Bring to the boil and bubble for 3-5 minutes. Using a fork, transfer the slices to a piece of nonstick baking paper and leave to cool; reserve the syrup.
6. Cut a cone shape from the top of each cake. Put ½ teaspoon lemon syrup and a little lemon curd into the hole and replace the cones. Spoon over ½ teaspoon syrup.
7. Put the butter into a bowl and whisk until fluffy. Gradually add the icing sugar and whisk. Add 3-4 tablespoons lemon syrup and whisk until fluffy. Stir in a little food colouring. Pipe a big swirl of icing on to the cupcakes and top with a lemon slice.