Adapted from Tamasin Day-Lewis's recipe in her fabulous book The Art of the Tart. Buy the book on Amazon here
I added the pastry lattice to the tart.
375 ready made and rolled shortcrust pastry, chilled
2 egg whites, beaten
3 tablespoons marmalade
grated zest and juice of 4 oranges
225g vanilla or golden caster sugar
125g unsalted butter, room temperature
1. Roll out three quarters of the ready made shortcrust pastry into a circle that's big enough to line the 22cm tart tin with a little overhang. Place the pastry circle into the tin, pressing it down at the edges. Shape the leftover pastry into a ball, cover with clingfilm and put this and the pastry circle in the fridge for 30 minutes.
2. Turn the oven to 190C (170C fan ovens).
3. To prepare to blind bake the chilled pastry circle, cut a circle of greaseproof paper and place it over the circle base, before covering with ceramic baking beans (or kidney beans or any kind of uncooked bean). Blind bake for 15 minutes, then remove the baking beans and greaseproof paper.
4. While the pastry is still blind baking, in a small bowl beat 1 egg white. Once baked, prick the pastry circle base and brush it with the beaten egg white before putting it back into the oven for another 5 minutes.
5. Remove again from the oven and using a knife spread the marmalade over the base of the tart as it cools.
6. In a large bowl, mix the orange zest with the butter and sugar, creaming them together until well combined.
7. Beat the 4 eggs until fluffy and pale, then add them to the butter, sugar and zest mixture.
8. Next place the bowl over a bain mairie (a pan of just simmering water), and stir the mixture until the sugar has dissolved.
9. Take off the heat, and stir the orange juice into the mixture.
10. Pour the mixture over the marmalade spread pastry base.
11. Take the chilled ball of leftover pastry and roll it out. Cut strips of pastry into approx 1cm wide strips, and carefully place the strips over the orange and marmalade filling. I didn't bother, but if you want to make it look especially smart you could also place a few long strips around the edge of the tart to create a rim.
12. In another small bowl whisk the 2nd egg white until fluffy, before brushing the pastry lattice (and the rim, if made) with the beaten egg.
13. Bake in the oven for approx 25 minutes. Serve warm or cold, with cream or custard.
This tart was idly baked while listening to Sorry I Haven't A Clue on BBC Radio 4