Grease and sprinkle with flour a 23 centimeters tart tin, then line with shop bought pastry, leaving about an inch of pastry hanging over the sides, prick the base with a fork and put in the fridge for 20 minutes to rest. Preheat oven to 180 degrees fan. While the pastry is resting stew your rhubarb. Place everything in a saucepan and simmer for 5 minutes or until the rhubarb is soft, take off heat and cool.
Remove your pastry case from the fridge, place in some greaseproof paper, and pour in some baking beans, spreading them so that they are completely covering the base, keeping it flat, then place your pastry shell in the hot oven and cook for 15 - 20 minutes. Remove from oven, take away the beans and greaseproof paper, then put back in the oven for another 10 - 15 minutes until golden.
While the pastry is baking, make the custard. Put the
Cream, milk and vanilla in a pan, bring to the boil, then
Take off the heat. Beat the sugar and eggs to combine,
Then pour in the hot liquid while whisking continuously.
Pour the custard mixture into a jug, cover with cling film to stop a skin forming then leave to cool slightly.
Check your pastry shell is completely cooked, then using a knife, scrape off any pastry that is over hanging the tart tin to form a nice neat edge.
Scatter the rhubarb over the bottom of the pastry case, and carefully pour in the custard. Place in the hot oven and bake the tart for 30 - 40 minutes until the custard is just set. Leave it to cool in the dish, then serve.