To make the pastry, put the flour, butter and salt into a food processor and whizz until the mixture resembles breadcrumbs. Add about ½ tbsp water and whizz again. If it doesn’t come together add another ½ tbsp water. Whizz again until the mixture comes together into a ball. Wrap in clingfilm and refrigerate for 30 minutes.
Preheat the oven to 200C, 400F, gas 6. Roll out the pastry and use it to line a 23cm (9in) loose-bottomed tart tin. Chill in the fridge or freezer. (In the fridge it will take about 30 minutes, in the freezer about ten. This stops the pastry shrinking when it goes into the oven.)
Put some greaseproof paper into the tin on top of the pastry and fill with baking beans or dried pulses.
Bake blind for 7 minutes, then remove the beans and paper, and return the tart case to the oven for another 5 minutes. Leave to cool.
If there are any little cracks or gaps in the base of the pastry, use whatever leftover pastry you have to fill them in – you just need to use tiny amounts. Turn the oven down to 180C, 350F, gas 4.
Chop the watercress very roughly. Melt the butter in a sauté pan and add the spring onions and watercress. Cook gently, stirring a little, until the watercress and onions are soft. Turn the heat up and cook until the moisture from the watercress has been boiled off. Set aside.
Cut the smoked salmon into pieces, if necessary.
Beat together the cream and eggs. Season. Put the watercress and onion mix and the smoked salmon into the tart case and slowly pour the custard over the top.
Return to the oven and bake until golden and just set in the middle (about 30 to 35 minutes). Leave to cool slightly – this is nice eaten warm rather than piping hot – then carefully remove the tart ring. Serve with a salad.
Tips for adjusting the recipe
Although I love cooking – and try new recipes all the time – I like the familiar, the trustworthy. I have lots of ‘core’ recipes I know will work and that I can adapt.
You can tweak this quiche recipe depending on what you fancy and what you have in the fridge. The only thing to be careful about is the moisture level of the other components. Tomatoes are better roasted – raw ones leach watery juices (making it difficult for the custard to set), while mushrooms need to be sautéed until they are a good colour and a lot of the moisture in them has been boiled off, otherwise you get a greyish, watery custard instead of a rich yellow one.
Custard needs to be tweaked according to what else was in the tart. A big, chunky filling that took up lots of space needed less custard (though you still had to have enough to make that lovely eggy set).
The custard can be more rich or less rich, depending on what you were trying to achieve. A custard in which you increased the amount of egg and reduced the cream, for example, would give a more ‘eggy’ set and be less luxuriously silky.
Heated, a quiche makes a perfect lunch or supper. But ready-made tarts are not cheap. If you master this basic recipe, you’ll be able to turn out countless perfect lunches or suppers for a fraction of the price.
Visit our salmon section for more salmon recipes, or try one of our other tart and quiche recipes, including a crustless quiche and Mary Berry's quiche lorraine.