Gap Between Filling and Crust in Tart

Our answer

Quiches and savoury custard based tarts, such as Nigella's Onion Tart from How to Eat, should have a soft set filling and there should not be a gap between the crust and the filling. From the description it sounds as if the filling is being cooked too long, or in an oven that is too hot. If it is cooked for too long then the filling will become too firm and be rubbery and unpleasant to eat.

First it is best to pre-bake the pastry base, before the filling is put in. This is called blind baking and the pastry case is lined with foil or baking parchment (parchment paper), weighted with rice, beans or ceramic baking beads and baked until set and golden. Usually this is done at about 200c/400F. Then the weights and foil/parchment are removed and the filling is added. You must turn the oven down and give it a few minutes to adjust to the new temperature before baking the tart with the filling. Usually the oven temperature should be between 150c/300F and 180c/350F. Bake the filled tart until the tart is almost set - it should still have a slight wobble in the centre as it will continue to set as it cools. If serving warm, let the tart stand for 15 to 20 minutes before cutting into it.