1. Place the flour, salt, cayenne, mustard and butter in a food processor and process for about a minute, until the mixture looks like fine breadcrumbs. Mix the egg yolk and cold water and, using the ‘pulse’ function on the processor, add just enough liquid to start to bind the pastry. Don’t over-process or the pastry will be tough instead of crumbly and light. Turn the mix out onto the work surface and gently form it into a ball with your fingertips. If you don’t have a food processor, sieve together the dry ingredients then rub the butter into the flour with your fingertips. Stir in the liquid with a round-bladed knife and again bring together with your fingertips.
2. Wrap the pastry in plastic wrap* and rest in the fridge for 15 mins while you start the filling, then roll out to 3mm thick and use to line a 23cm loose-bottomed round tart tin. Rest in the fridge for a further 15 mins while the oven heats to 190oC on Bake and then bake ‘blind’ (see ‘Tips and tricks’ below for how to do this). After removing the pastry case, reduce the oven temperature to 180oC on Bake.
3. Meanwhile prepare the filling. Heat the butter and oil in a large frying pan, add the onions, garlic, potatoes and thyme and cook over a low heat, turning occasionally. Raw potatoes need to be sliced thinly and will take 20–30 mins at a low temperature to cook through; cooked potatoes will be quicker but cook them gently so they don’t fall apart. Add any optional extras too.????
4. Whisk together the eggs, crème fraîche and seasoning.
5. Pile the potato mix and cheese into the cooked pastry case and pour the egg mixture over it. Bake for 30–35 mins at 180oC until lightly golden brown and just set in the centre. Serve warm or cold with a green salad and crusty bread.
Tips and tricks
*Pastry can be made the day before, wrapped and stored in the fridge, just let it warm up at room temperature for about 30 mins before you try to roll it out or it will crumble and break.
Baking blind: For some dishes it is preferable to bake the pastry case empty or ‘blind’, before you add the filling. This ensures the pastry is crisp rather than the filling taking all the heat and the pastry remaining undercooked and soggy. Line the uncooked pastry case with baking paper you’ve scrunched up then flattened out, fill with ‘baking beans’ or raw rice (see below). It is essential to support the sides of the tart in this way to prevent them falling in and to stop the base rising. However, this will slow down the cooking so remove the baking beans after 15 minutes, once the pastry is ‘set’. Return the pastry to the oven for a further 10 minutes or until the base is cooked and golden brown.
Using rice for ‘blind-baking’: Put a generous amount of rice into a roasting bag and this can be put directly into the pastry case. The rice moulds easily to support the sides of the tart and keep the base flat. Cool and store the rice in the bag. It can be used over and over again, just make sure the rice is completely cold before you seal the bag or the condensation will cause the rice to go mouldy.
To freeze quiche: Let the tart cool completely, pack into a freezer bag or box, seal and freeze for up to 1 month. To serve, unwrap and thaw at room temperature for 4 hrs, then reheat at 180oC on Bake or at 160oC on Fan Bake for 20 mins. Alternatively, cut into portions and freeze the pieces on an open tray. As soon as the tart is frozen, pack into a freezer bag or box with a sheet of baking paper between each portion.