1. Roll out pastry and line a 23 x 2.5cm loose bottom fluted flan tin. Trim and neaten edges. Press pastry into flutes. Prick the base with a fork, line with foil, shiny side down, chill for 1hr.
2. Fill with dry beans.
3. Cook on a baking sheet in a pre heated oven 180°C for 15 minutes, then remove foil and bake for a further 5-8 minutes or until pastry is cooked.
4. Mix the cornflour, castor sugar and lemon zest in a medium saucepan, strain and stir in the lemon and orange juices.
5. Stir in water and Major Lemon Fruit Base.
6. Cook over medium heat, stirring constantly, until thickened and smooth.
7. Once the mixture bubbles, remove from the heat and beat in the butter until melted.
8. Beat in the egg yolks and the whole egg.
9. Return to medium heat. Keep stirring for a few minutes until the mixture thickens. Take off the heat and set aside.
10. Put the egg whites in a large bowl. Whisk to soft peaks, then add half the sugar, a spoonful at a time, whisking between each addition without overbeating.
11. Whisk in the cornflour, then the rest of the sugar as before until smooth and thick.
12. Reheat the filling and fill pastry case.
13. Put spoonfuls of meringue around the edge of filling then spread until it just touches pastry. Pile the rest in the middle, then give it a swirl.
14. Return to oven until crisp and slightly coloured. Leave for 1 hour before serving.