Melt the sugar in a 20cm ovenproof frying pan over medium heat until it caramelizes into a golden brown liquid.
Remove the pan from the heat and stir in the butter carefully with a wooden spoon.
Stir for 3 minutes until smooth, then arrange apricots cut-side down in the caramel and cool for 20 minutes.
Preheat your oven to 200°C.
Roll out the pastry on a floured surface and cut a circle slightly larger than the pan.
Place the pastry over the fruit, tuck in the edges, and prick the surface with a knife.
Bake for 25 minutes until the pastry is golden-brown and the fruit is cooked.
Let the tart stand for two minutes, then carefully invert it onto a large serving plate.
Serve the tart warm with crème fraîche or ice cream.