Mix the flour with the sugar and salt and place in a food processor.
Add the butter, cut into pieces, and blitz with the egg yolk to a crumbly mixture.
Quickly knead with your hands on a floured surface to a smooth dough and form a ball. Wrap in cling film and chill for 30 minutes.
Preheat the oven to 180°C (160°C fan, gas 4). Grease the tart tin with butter. Roll out the pastry on a floured surface and use to line the tin, letting the excess over hang the edge. Prick the pastry base several times with a fork.
Line the pastry case with baking paper and weight down with baking beans. Bake in a preheated oven for 15 minutes.
Remove the baking paper with beans and carefully trim off the overhanging edge. Sprinkle the base with the crumbs.
Wash the apricots, halve, remove the stones and arrange them in the pastry case, cut surface up.
Mix together the eggs, cream, crème fraîche, vanilla seeds and sugar. Bake for 45 minutes until golden brown. Remove and allow to cool. Sprinkle with icing sugar. Serve with whipped cream.