- In a food processor, combine the flour, icing sugar, baking powder and salt. Add the butter and pulse a few seconds at a time until pea-sized pieces form. Add the yogurt. Pulse again until the dough just begins to form. Remove the dough and shape into a disc.
- On a lightly floured surface, roll out the dough into a 19 x 6-inch (40 x 15 cm) rectangle with a thickness of about 1/8 inch (3 mm). Line a 14 x 4-inch (35 x 10 cm) rectangular tart pan with a removable bottom. Remove any excess dough. With a fork, prick the dough. Refrigerate for 30 minutes.
- With the rack in the lowest position, preheat the oven to 400°F (200°C).
- Bake for about 15 minutes or until the crust is golden brown. Let cool slightly.
- In a bowl placed over a pot of simmering water or in the microwave, melt the chocolate with the cream. Remove the bowl from the heat. Whisk in the brown sugar. Add the eggs and whisk until smooth. Stir in the flour. Spoon into the crust.
- Bake for 10 to 12 minutes or until the filling is set at the edges but still very soft in the centre.
- Serve the tart hot or warm.
This tart freezes well once baked. Let thaw and reheat for 5 minutes in an oven preheated to 350°F (180°C) before serving.