Tarte à l'Oignon

An onion tart whose case is blind-baked and sealed before a wet custard goes anywhere near it.

Egg. Vegetarian, but not vegan — contains egg, dairy (butter), dairy (double cream), dairy (milk). Vegetarian only if you leave out the optional lardons, which are pork.

Ingredients

For the case

• 1 batch pâte brisée, as on its own page, blind-baked and sealed

For the filling

• 1 kg onions, sliced thin
• 40 g butter
• 100 g smoked lardons, optional
• 3 eggs
• 200 ml double cream
• 100 ml milk
• a grating of nutmeg
• salt and white pepper

Method

1. THE CASE IS BLIND-BAKED AND SEALED BEFORE THE CUSTARD GOES IN, and for this tart that is not optional. The filling is three eggs and three hundred millilitres of liquid poured into raw pastry: unsealed, it soaks through the base in the fifteen minutes before the custard sets, and what you cut into is a cooked tart sitting on wet dough. The pâte brisée page gives the egg-white seal; this is the dish it exists for.
2. THE ONIONS ARE COOLED BEFORE THEY MEET THE EGGS. Hot onions scramble the custard on contact and it sets grainy and splits in the oven. Spread them out to cool for twenty minutes -- which is also when the case is baking, so it costs nothing.
3. A KILO OF ONIONS LOOKS ABSURD AND IS RIGHT. They cook down to about a fifth. Half that quantity gives a custard tart with some onion in it.
4. AND THE CUSTARD IS POURED IN WITH THE TART ALREADY ON THE OVEN SHELF. Carried across the kitchen full, it slops over the rim, and custard baked onto the pastry edge glues the tart into the tin.
5. Pâte brisée made as on its own page, lined into a 24 cm tin, blind-baked and sealed with egg white.
6. Butter in a wide pan. The lardons fried first if using, and lifted out.
7. Onions in with a good pinch of salt, covered 10 minutes until they give up their water.
8. Lid off and cooked over a medium-low heat 30 to 35 minutes until soft, golden and sweet, but NOT browned -- dark onions make a bitter tart.
9. Spread on a plate and COOLED 20 minutes.
10. Eggs, cream, milk, nutmeg, salt and white pepper whisked together, then passed through a sieve.
11. The cooled onions and lardons spread in the case and levelled.
12. The case set on the oven shelf, and the custard poured in THERE, to just below the rim.
13. Baked at 170C for 30 to 35 minutes until barely set -- a slight wobble at the centre. Cooked until firm, it will be rubbery once cool.
14. Rested 20 minutes and eaten warm rather than hot.

Our own recipe. This one was written for this site rather than taken from anywhere, so there is no source to point you at. The quantities and the order of the steps are choices, not the only way to do it.

Filed under France · All recipes