Pre-heat the oven to 160C Fan/180C/350F/Gas Mark 4, and line a cupcake tin with paper cases
Mix together the caster sugar and butter until smooth and fluffy, for best results use an electric mixer
Add the eggs and lemon zest and whisk them in, again using an electric mixer if you can
Mix in the self raising flour, this time gently and with a hand whisk, and then divide the batter between the paper cases
Bake them for 20-25 minutes until they are golden brown and a skewer inserted in the centre comes out clean. Leave them to cool completely on a cooling rack
Using a cupcake corer or a knife, make holes in each cupcake and fill with the lemon curd
To make the Italian meringue put the caster sugar and water in a pan, stir them together then bring to a boil. When the mixture reaches 112C (235F), take it off the heat and pour the sugar syrup into a jug
While the sugar water is coming to a boil, in a stand mixer or using an electric whisk, whisk up the egg whites with the cream of tartar until they reach soft peak stage (foamy and they are just starting to holding their shape on the whisk but not quite)
Then, keeping the mixer running on a medium speed, pour in the hot sugar syrup slowly. Be careful not to let the sugar syrup hit the side of the bowl. Turn the mixer speed up to high and mix until the meringue is white and shiny and holds its shape, and the bowl of the mixer feels cool
Put the meringue in a piping bag fitted with a star nozzle and pipe it on top of the cupcakes. Or spread on with a spoon. Use a kitchen blowtorch to brown the meringue all over
Serve immediately, store leftovers in the fridge and and eat within 2 days