• Preheat the oven to 180'C (170'C fan) / Gas 4. Fill a 12-hole baking tin with cupcake cases and set aside while you make the cake batter.
• Add the butter and sugar to a large mixing bowl and beat with an electric whisk until pale and creamy. (TIP: If the butter is hard, zap it in the microwave for 10-15 seconds before adding it to the mixing bowl to make it easier!)
• Crack the eggs into the mixing bowl and add the lemon zest. Beat again for 30 seconds to combine. Scrape down the sides of the bowl using a spatula.
• Sift in the self-raising gluten free flour and xantham gum, add the milk, and then beat together with the electric whisk until everything is fully combined. You want a fairly thick batter which looks light and fluffy.
• Spoon the mixture evenly between the cupcake cases and then place in the centre of an oven and bake for 20-22 minutes. The cupcakes are done when they are well-risen, golden on top, and a skewer inserted in the middle comes out clean. Take the cupcakes out of the oven, set to one side to cool slightly and turn the oven down to 110C / Fan 90C / Gas Mark 1/4.

To make the meringue topping:

• Add the egg whites to a large bowl and beat with an electric whisk until they start to form stiff peaks (aka when you can turn the bowl upside down and they won't budge!).
• Add the white wine vinegar to the egg whites and then add the caster sugar 1 tbsp at-a-time while still whisking, until they form glossy peaks. You'll know it's done when you rub a tiny bit of the mixture between your fingers and it doesn't feel grainy.
• Spoon the meringue mixture into a piping bag fitted with a 1M nozzle (or nozzle of choice!).

Fill and top the cupcakes:

• Using a sharp knife, cut a small well in the centre of each cupcake. Fill with lemon curd (around 1 tsp per cupcake).
• Pipe the meringue onto the top of the cupcakes in swirls and then place in the oven for a further 30 minutes.
• Remove from the oven and cool before eating. If you like, you can finish them off with a quick blast of the blowtorch - just mind the cake cases don't set fire!