Sift the
flour into the bowl and rub in the butter with your fingertips until the
mixture resembles fine breadcrumbs. Add the mascarpone and mix with a
flat-bladed knife, using a cutting action, until the mixture begins to
form lumps which leave the side of the bowl. Turn the dough out onto a
lightly floured surface and gently gather into a smooth ball. Flatten
slightly into a disc, then cover in plastic wrap and refrigerate for 30
minutes. Preheat the oven to 325F, Gas 3. Lightly grease a 23cm (9")
metal pie dish. Put a baking tray in the oven to preheat. Heat the oil
in a frying pan and cook the bacon and onion over medium heat, stirring
occasionally, for 5-7 minutes, or until just browning. Stir in the
parsley. Set aside to cool. Divide the pastry into two portions, one
slightly larger than the other. Roll out the larger portion between two
sheets of baking paper until large enough to line the base and side of
the pie dish. Line the pie dish. Put the bacon mixture in the pastry
shell and make six well spaced holes in the mixture with the back of a
spoon. Crack an egg into each of the holes. Brush the rim of the pastry
with water. Roll out the remaining pastry between the baking paper until
large enough to cover the top of the pie. Lift it onto the pie, trim the
excess pastry and seal the edges. Re-roll the trimmings and make leaves
to decorate the pie. Brush with egg yolk and bake on the hot tray for 40
minutes; cover if it browns too quickly. Leave for 10 minutes, then
serve.
