Mix the flour and icing sugar in a bowl and rub in the butter until it looks like fine breadcrumbs.
Stir the egg, lemon juice, and two tablespoons of water together.
Work the liquid into the flour mixture with a knife to form a dough, adding more water if necessary.
Knead the dough into a ball, wrap it in cling film, and chill for 15 minutes.
Cut the fruit into 1cm pieces.
Melt butter in a pan, add fruit, sugar, zest, and alcohol, then simmer for 10 minutes.
Cool the fruit mixture, stir in mascarpone if using, and chill.
Preheat your oven to 200°C.
Roll the pastry to 2-3mm thick and cut twelve 8.5cm circles to line a bun tray.
Cut twelve 6cm circles from the remaining pastry for the lids.
Fill the cases with fruit, dampen the edges, and seal with the lids.
Make steam holes in the lids, brush with milk, and sprinkle with granulated sugar.
Bake for 25-30 minutes until the pastry is golden-brown.
Cool in the tin for five minutes before serving.