Preheat the oven to 190°C.
Grease six small ANTA mugs.
Place the butter, caster sugar and lemon zest in a large bowl and beat together until light and fluffy.
Gradually beat in the egg.
Sift the flour into the mixture and fold in using a metal spoon together with the lemon juice.
Spoon the mixture into the mugs and place on a baking tray.
Bake for 15 minutes, until risen, golden and firm to the touch.
For the meringue, put the egg whites in a grease-free bowl.
Use an electric mixer to whisk until stiff.
Gradually whisk in the caster sugar to form a stiff, glossy meringue.
For the lemon curd.
Melt the butter, sugar, lemon zest and juice in a bowl over barely simmering water.
Add the yolks and whisk all the ingredients together, cook for 10 -15 minutes, stirring occasionally until the mixture is thick and creamy.
Spread the lemon curd over the hot cupcakes then swirl over the meringue.
Return the cakes to the oven for 4–5 minutes until the meringue is golden.
