Onion Tart – sweet, slow cooked onions in a cheesy, herb crust
Over Christmas I forgot to keep an eye on my onions in store and found that one or two of them had gone off. They should keep for a while longer yet but I’m going to start making some onion soup for the freezer!
This light, creamy onion tart is a great way to make the most of your onions and if you’ve got some of the mild ‘Kelsey’ type left then use them up before it’s too late!
Serves 4,takes about 1hour, 45 minutes
For the pastry:
175g plain flour
Pinch of salt
50g parmesan cheese, grated
Teaspoon thyme leaves
75g butter, chilled
2-3 tablespoons cold water
For the filling:
900g (about 5) onions (preferably mild)
2 egg yolks
250ml double cream
½ teaspoon ground nutmeg
Salt and pepper
Teaspoon thyme leaves
- Make your pastry in a food processor if you have one otherwise make in the usual way.
- Put the flour, salt, and butter together in the processor and blitz until you have fine breadcrumbs. Add the parmesan and thyme leaves and pulse briefly.
- Add 2 tablespoons of the water and pulse to form a dough. Add more water if necessary.
- Pop in a freezer bag and seal then rest in the fridge for 30 minutes or so.
- Whilst the pastry is chilling, prepare the onions. I find it easiest to cut in half lengthways then cut the root off and peel. Lay flat on a chopping board then slice as thinly as you can.
- Melt the butter in a heavy based, lidded pan, add the onion slices and try and coat thoroughly in the butter. Pop the lid on and turn the heat low. Leave to cook for about 30-40 minutes, stirring fairly often.
- The onions will be really tender but still pale and juicy. Take the lid off and leave the juices to evaporate over a low heat for about 5 minutes.
- Leave to cool whilst you cook the pastry.
- Grease a 23cm(9”) fluted, loose bottom flan case and preheat the oven to 190C/fan170/ 375F/gas 5.
- Roll out the pastry and line the tin, pressing down into the sides. Line with greaseproof paper then fill with baking beans. Put on a baking tray and pop in the oven for 10 minutes. Remove the beans and paper and return to the oven for another 5 minutes until pale golden brown.
- Turn the oven down to 180C/160fan/350F/gas 4.
- Put the egg and the egg yolks into a bowl and stir together then whisk in the cream. Add the nutmeg and a good grinding of salt and pepper.
- Carefully place about half the onions into the flan case then pour in half the cream mixture. Lay over the remaining onions and pour in as much of the cream filling as you can. Leave a little room for expansion! Grind over a little more black pepper.
- Carefully place in the oven and cook for about 45 minutes. The top will puff up a little and turn a lovely golden brown. The flan will feel firm to the touch.
- Leave to cool as the tart is best served warm rather than hot.