Serve with softly whipped cream.
For the Pastry:
- 175g plain flour, sifted
- 50g icing sugar
- 100g very cold butter, cut into cubes
- 1 egg yolk plus a tablespoon of iced water
For the Filling:
- 3 egg yolks
- 75g caster sugar
- 250mls crème fraîche
- ½ vanilla pod (split lengthways and seeds scraped out).
For the Rhubarb:
- 500g rhubarb
- 150g sugar
- Lightly butter a 23cm (9-inch) tart tin and put it in the fridge. Put the flour, and icing sugar in a food processor and aerate with a couple of quick on/off pulses.
- Add the butter and process until the mixture resembles fine breadcrumbs. Add the egg yolk and water (if necessary) and process until the pastry just draws together.
- Turn it out on to a lightly floured work surface and knead briefly to form a flat round. Wrap the pastry in cling film and chill for at least 20 minutes before rolling out.
- Pre-heat an oven to 190C/gas 5. Roll out to a round at least five centimetres (two inches) larger than the tin.
- Wrap the pastry around the rolling pin, lift into place and unroll loosely over the chilled tin.
- Gently lift and press the pastry into the tin to line, then roll the rolling pin over the top of the tin to trim off the excess pastry.
- Line the chilled pastry case with baking parchment, fill with baking beans and cook for 10 minutes. Carefully remove the beans and paper and cook for another 10 minutes or a little longer, until a light biscuit brown colour.
- Turn down the oven temperature to 140C.
For the Rhubarb - this can be done beforehand:
- Set the oven to 150C.
- Cut the rhubarb into 10cm lengths. Place in a roasting tin. Mix the vanilla seeds with sugar and sprinkle over the rhubarb and roast in the oven until the rhubarb is tender - about 20 minutes.
For the Filling:
- Whisk the egg yolks and sugar in a bowl with a metal whisk until smooth fold in the crème fraîche. Pour into the pastry case.
- Lay the rhubarb on top.
- Bake in the oven for 40-45 minutes, or until only just set. The custard should still be fairly wobbly in the middle, as it will continue to set as it cools.
- Remove from the oven and allow to cool before cutting and serving. Serve with softly whipped cream.