Preheat the oven to 175°C.
Roll out the pastry on a lightly floured surface to ½cm thickness and cut a round of pastry 2-3 inches larger than an 8 inch springform fluted tart tin. Line the flan case using the pastry, pressing in well then prick the base. There should be pastry overhanging, but don't cut it off.
Prepare the filling by whisking together the milk and crème fraîche. Fold in the chopped peppered beef, salt beef, basil and pine nuts. Fill the pastry with the filling, making sure to level off. Fold the overhanging pastry back over the filling, crimping slightly at the edge to create a wave pattern; brush the exposed pastry with the beaten egg yolk.
Bake the tart for 40-45 minutes until the pastry if golden and cooked and the filling is set. 10 minutes before it is finished, remove and place a few basil leaves and a slice of prosciutto in the centre.
Return to the oven to finish cooking. Remove after 10 minutes and allow to cool a little before turning out. Transfer to a serving plate.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home.