For pastry combine flour, sugar and butter in a large bowl or food processor. Cut butter in until it is in tiny bits. Add yolk and gather dough into a rough ball. Knead lightly. Press dough into the bottom and halfway up the sides of a 10 springform pan. Press parchment paper over the dough and freeze for a few hours to overnight. Bake pastry in a preheated 375F oven for 15 minutes. Cool and remove paper gently. Combine berries with maple syrup, balsamic and half the sugar. Place in pastry. Whisk eggs, yolks, remaining sugar, cream and vanilla. Pour over berries. Bake 45 to 55 minutes or until custard is set in the centre and top has browned. Cool at least 15 minutes before removing side of pan. Serve warm or cold.