To make the pastry, mix the butter and sugar together until light and cream coloured.
Add the egg yolks, then flour and mix to form a soft dough. Cover with cling film, place in the fridge and chill for 30 minutes.
Preheat the oven to 180ºC. Roll out the pastry and line a 29cm fluted tart tin. Prick the base all over with a fork and bake blind* for 10 minutes. Remove from the oven, take the baking paper and beans off and bake for another 2 minutes uncovered. Remove from the oven and allow to cool whilst you prepare the filling.
Whisk the eggs, egg yolks, sugar, vanilla and corn flour together in a bowl. In a saucepan heat the cream and thyme sprigs. Just before boiling point, remove and add to the egg mixture while whisking constantly.
Pour the custard into the tart shell and reduce the oven temperature to 170ºC. Scatter the berries over the custard, then place in the oven and bake for 25-30 minutes until lightly set.
Leave to cool slightly, then remove from the tin. Serve warm or at room temperature, with fresh blueberries.
* To bake blind: Cut a piece of baking paper just larger than the tart tin. Press the paper onto the pastry, then add baking beans (available at specialist baking shops) or rice. This acts as a weight to keep the pastry from puffing up in the oven. Bake for about 10 minutes with this on, and then a few minutes with baking paper and beans/rice removed, to crisp up the pastry.Chef's tip:
Replace the thyme with bay leaf for a spicier more robust flavour.
Reprinted with permission of Sasko.