For the pastry

For the pastry

175g plain flour

100g cold butter, cut in small pieces

1 tbsp icing sugar

1 egg yolk

For the filling

2 level tbsp corn flour

100g golden caster sugar

finely grated zest 2 of large lemons

125ml fresh lemon juice (from 2-3 lemons)

juice 1 small orange

85g butter, cut into pieces

3 egg yolks and 1 whole egg

For the meringue

4 egg whites, room temperature

200g golden caster sugar

1 For the pastry, put the flour, butter, icing sugar, egg yolk (save the white for the meringue) and 1 tbsp cold water into a food processor. Using the pulse button so the mix is not overworked, process until the mix starts to bind. Tip the pastry onto a lightly floured surface, gather together until smooth, then roll out into a big rectangle. Trim and neaten the edges. The pastry is quite rich, so don't worry if it cracks, just press it back together. Prick the base with a fork, line with foil, shiny side down, and chill for 1⁄2-1 hour (or overnight).

2 Cut the pastry in portion size rectangles. Put a baking sheet in the oven and heat oven to 200C/fan 180C/gas 6. Bake the pastry 'blind' (covered with dry beans) for 10 mins, then remove the foil and bake for a further 5-8 minutes until the pastry is pale golden and cooked. Set aside. (Can be done a day ahead if you want to get ahead.) Lower the oven to 180C/fan 160C/gas 4.

3 While the pastry bakes, prepare the filling: mix the corn flour, sugar and lemon zest in a medium saucepan. Strain and stir in the lemon juice gradually. Make orange juice up to 200ml/7fl oz with water and strain into the pan. Cook over a medium heat, stirring constantly, until thickened and smooth. Once the mixture bubbles, remove from the heat and beat in the butter until melted. Beat the egg yolks (save white for meringue) and whole egg together, stir into the pan and return to a medium heat. Keep stirring vigorously for a few minutes, until the mixture thickens and plops from the spoon. (It will bubble, but doesn't curdle.) Take off the heat and set aside while you make the meringue.

4 Put the egg whites in a large bowl. Whisk to soft peaks, then add the sugar a spoonful at a time, whisking between each addition without overbeating until smooth and thick.

5 Quickly reheat the filling and pipe it onto the pastry rectangles. Immediately pipe the meringue around the edge of the filling, so it touches the surface of the hot filling (and starts to cook). Use a blowtorch to colour the meringue. Eat the same day.