These beautiful fruit tarts use Anna Olson’s simple Pate Sucree start as the base and are filled with juicy blackberries and airy meringue.
Cut the dough into 8 equal pieces. On a lightly floured surface, roll out each piece of dough into a circle just over ¼-inch (6 mm) thick. Line 8 individual 4-inch (10 cm) removable-bottom tart shells with the pastry and trim away excess pastry. Chill the shells for 20 minutes.
Preheat the oven to 350 °F (180 °C). Place the chilled shells on a baking tray and dock the bottoms of the pastry with a fork. Bake the shells for about 20 minutes, until they brown just a little at the edges. Cool the shells to room temperature.
Melt the white chocolate by placing it in a metal bowl resting over a pot of barely simmering water, stirring gently until melted. Use a pastry brush to brush a thin layer of the chocolate over the bottom of each cooled tart shell (this prevents the filling from seeping into the pastry shells). Chill the shells until ready to fill.
For the blackberry filling, bring 2 cups (500 mL) of the blackberries up to a simmer with the sugar, stirring occasionally and simmering for about 5 minutes until the berries have softened and let out juices. Use a potato masher or spoon to crush the berries a little. Whisk the cornstarch with 2 Tbsp (30 mL) of cool water and add this to the pot, returning it to a full simmer while stirring until thickened, about 2 minutes. Add the remaining 1 cup (250 mL) of berries and vanilla, return to a simmer and then remove the pot from the heat. Cool the berries to room temperature and then chill the filling.
To assemble the tarts, preheat the oven to 400 °F (200 °C). Spoon the blackberry filling into the chilled tart shells, arranged on a baking tray.
Using electric beaters or a stand mixer fitted with the whip attachment, whip the egg whites and cream of tartar on high speed until foamy and then gradually add the sugar and icing sugar while whipping, continuing until the whites hold a medium peak (the meringue peaks with a curve but not a full curl when the beaters are lifted). Dollop the meringue (for a rustic look) or pipe the meringue using a large star tip on top of the berry filling. Bake the tarts for 5 minutes, until the meringues brown on the surface. Allow the tarts to cool, then chill before serving.