1 x loose based 9" flan tin
1 x piping bag
1 x plain 1cm piping nozzle
For the pastry
200g plain flour
125g unsalted butter, chilled and cubed
50g icing sugar
1 large egg, beaten
For the filling
1kg rhubarb, trimmed & cut into 2 inch lengths
125g castor sugar
Zest of 1 orange
For the meringue
4 egg whites
220g castor sugar
First make the pastry.
Sift the flour and icing sugar into a bowl and add the cubed, cold butter. Rub the butter into the flour with your fingertips, until it resembles coarse breadcrumbs. Keep everything as chilled as possible to ensure a light, flakey result to your pastry. Add the egg and mix to bring together. Turn onto a lightly floured work surface and gather into a ball. Wrap in clingfilm and chill for 20 minutes, until firm but not hard.
Roll out the pastry on a lightly floured work surface and line flan tin. Prick the pastry base a number of times with a skewer, being careful not to pierce the whole way through. Chill for a further 10 minutes.
Meanwhile make rhubarb filling.
Preheat the oven to 150C. Place the prepared rhubarb in a baking tray/oven proof dish, with the sugar and orange zest and toss to coat. Cook for approximately 20 - 25 minutes until just tender. Drain well and then leave aside to cool.
While the rhubarb is cooling, line the pastry case with parchment paper and fill with baking beans. Bake blind for 15 - 20 minutes until the pastry case is almost fully cooked and the paper easily comes away from the pastry. Remove the paper and baking beans, brush lightly with beaten egg and bake for a further 5 - 10 minutes until the pastry is fully cooked and a light gold colour.
Make the meringue
Put the egg whites in a spotlessly clean and dry bowl of a food mixer and whisk to soft peaks. Gradually add half the sugar and continue to whisk until you have glossy, white peaks. Add in the remaining sugar and whisk for another minute until the mixture is smooth, thick and glossy.
Turn the oven temperature down to 140C. Fill the pastry case with the cooked, drained rhubarb. Spread three quarters of the meringue over the top of the tart and then pipe the remaining meringue, in small peaks, over the surface. Bake for about an hour at 140C until the mixture is crisp on the outside and golden on top. If it's not colouring enough for you, you can give it one final minute under the grill but watch carefully!
Allow to cool before removing from the tin and serving.