Preheat the oven to 180 degrees Celsius (350 Fahrenheit) and line a 12 hole muffin tin with paper cupcake liners. Remove the butter and eggs from the refrigerator and allow them to come to room temperature before making the cupcakes.
Place all the ingredients into the bowl of a food processor and process until you have a smooth, thick batter. Divide the batter between the cupcake liners. Bake for 15 to 20 minutes or until cooked and remove from the tray and place on a wire wrack to cool.
To make the lemon curd place the egg, egg yolk and sugar in a saucepan and whisk until smooth. Add the butter, juice and zest and place over a medium low heat. Whisk until thickened, this will take between 5 to 10 minutes. The mixture will be ready when you can see a slight trail from the whisk in the mixture. It will thicken further when refrigerated. Refrigerate overnight.
Cut a circle in the top of each cupcake and scoop out some of the cupcake from the center and fill with lemon curd. Trim the circle you removed earlier and then replace on the cupcake. Repeat with each cupcake.
Preheat the oven to 160 degrees celsius.
To make the meringue topping, place a saucepan of water over a medium heat and bring to a simmer. Place the bowl of a mixer over the heat and add the eggs, lemon juice and sugar and whisk by hand until the sugar is dissolved. Remove from the heat and attach to a stand mixer and whisk at a medium speed for 10 minutes, or until thick and glossy and stiff peaks form.
Prepare a piping bag and paint stripes of food colouring along the piping bag (you can use a small paint brush or cotton tip for this) and fill with the meringue mixture. Pipe the mixture on top of the cupcakes and bake for 5 to 7 minutes, or until firm and lightly golden. Alternatively use a hand held torch.