Preheat the oven to 180°C and lightly grease a 25cm loose-based flan tin
Roll the pastry on a lightly floured surface to a 30cm square then line the tin with the pastry and leave the excess to hang over the edge. Chill for 30 minutes.
Remove from the fridge and line the base of the pastry with baking parchment and fill with baking beans. Place on a baking sheet and bake blind for 20 minutes. Remove the beans and baking parchment and return to the oven for another 5 minutes to cook the base.
Leave to cool slightly then trim the pastry around the edges and reduce the oven temperature to 150°C
For the filling, beat the eggs with the crème fraiche and season well with salt and freshly ground pepper. Fold in the cheese and spoon the mixture onto the base of the tart. Top with the asparagus and cover with the remaining cheese.
Bake in the oven for a further 30 minutes until set.