Step 1

Place the flour, sugar and butter in a kitchen whizz and blitz until it resembles fine breadcrumbs.

Step 2

Add the egg, and blend to form a soft dough. Add water if needed. Wrap in cling film. Refrigerate for 30 minutes.

Step 3

Preheat the oven to 180C.

Step 4

To make the filling, melt the butter in a saucepan, add the apples and stir over medium heat for 3 or 4 minutes. Add the rhubarb and stir for 3 or 4 minutes until starting to soften. Add sugar, cinnamon and zest. Stir until the sugar has dissolved. Set aside to cool until needed.

Step 5

Roll two-thirds of the pastry to 3mm thick, and line a 22cm pie tin. Bake blind for 15 minutes or until the pastry is almost completely cooked. Remove from the oven.

Step 6

Place the cooled rhubarb and apple in the tin. Roll the remaining pastry into a square and cut 1cm strips. Arrange on top in a lattice.

Step 7

Return to the oven for 20 minutes, till the pastry is golden. Serve with cream or custard.