Method

• 1.
  Lightly grease the tart pans.
• 2.
  Place the flour, butter, sugar and cocoa in a food processor with 1/4 teaspoon salt. Process until the mixture resembles fine breadcrumbs. Add egg yolk and 1 tablespoon of chilled water and process until mixture forms a smooth ball. Wrap in plastic wrap and refrigerate for half an hour. Roll out pastry on a lightly floured surface and use to line tart pans. Refrigerate for 15 minutes.
• 3.
  Preheat the oven to 190°C.
• 4.
  Line tarts with non-stick baking paper and fill with rice or pastry weights. Bake in oven for 15 minutes. Remove paper and weights and return to oven for 5 minutes until dry and crisp.
• 5.
  Place chocolate in a bowl over a pan of simmering water and melt without stirring. Remove from heat and scrape in the vanilla bean seeds (do not stir). Set aside to cool slightly.
• 6.
  Whisk mascarpone and cream until thick. Add chocolate and stir to combine. Fill tarts with chocolate cream, pile berries on top and brush with jam.