Preheat the oven to 180°C.

Slice the plums into 1cm thick wedges and discard the pips. Over medium heat, cook the plums in the Cassis, sugar and Vanilla until they begin to soften and turn a deep red in colour. Strain the plums and set aside but do not throw away the juice.

In the same pan, simmer and reduce the juice until it becomes thick and syrupy. Add a squeeze of lemon juice to taste.

Roll out the pastry and cut a large round to make the pie base. Grease a pie dish and carefully press your pastry into the dish. Prick the base of the pastry with a fork, line with baking paper, fill with beans and blind bake the pastry for 15 minutes until golden brown. Remove the baking beans and pour the plums into the pie shell, covering them with the reduced plum sauce.

Roll out your leftover pastry and, using a ravioli slicer, cut the pastry into 12 1cm-wide strips to make the lattice topping. Carefully lay half of the pastry strips parallel to each other leaving a 2cm gap between strips. Then lay the other half of the strips at a 90-degree angle from the first strips. Make an egg wash by beating the egg and milk together and lightly brush the pastry, finishing with a dusting of sugar.

Place in a hot oven for 10 minutes until the pastry has turned golden brown.

Serve hot with a dollop of thick cream or homemade custard.

Tips: Cassis, or Crème de Cassis, is a sweet fruity liqueur made from blackcurrants.