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The starter, Regional

Alsatian onion tart

Alsatian onion tart is a starter for 6 made with shortcrust pastry, slowly cooked onions, and a custard of eggs, cream, and milk. It takes 40 minutes of active work, the dough and onions are made the day before, and only the assembly happens the morning of. It's rated easy, costs about €1.10 per person, and success depends on cooking the onions very gently without browning.

I'm suggesting a real Alsatian onion tart, served warm, scented with nutmeg, filling the kitchen with its smell before it even reaches the table.

Alsatian onion tart
For
6 people
Work
40 min
Total time
2 h 50
Prep
Prepared the same day
Difficulty
Easy
Cost per person
€1.10
Calories per person
420 kcalcalculated by Kiloach, your weight coach

Under a golden shortcrust crust, the onions melt into a tender, faintly sweet mass, barely lifted by nutmeg. The egg and cream custard keeps it soft without ever feeling heavy, and it's best eaten warm, never piping hot, so the flavors can fully come through.

This is a cold season starter, perfect for opening a family meal or a dinner with friends built around slow cooked mains. Kids tend to like it too, thanks to the mellow sweetness of the cooked onions, and it fits easily into a rustic menu, ahead of a braised meat dish or a hearty stew.

The schedule

What happens when, so you can be with your guests instead of in the kitchen.

  1. The day before 2 steps, 40 min
  2. The same day 2 steps, 50 min
  3. Before the guests arrive Nothing to do
  4. When it's time to serve 1 step, 10 min

The day before, make the dough and cook the onions down, both keep well in the fridge wrapped tightly. The morning of, roll out the dough, blind bake the crust, then fill and bake the tart. Just before guests arrive, let it cool slightly, and at serving time, warm it through in a low oven for a few minutes before slicing.

The ingredients

6 people

Pantry

  • Flouroften in the pantry 250 g
  • Nutmegoften in the pantry 1 pinch
  • Saltoften in the pantry 1 pinch
  • Pepperoften in the pantry 1 pinch

Dairy

  • Butter 125 g
  • Eggs 3
  • Heavy cream 20 cl
  • Milk 10 cl

Fruits and vegetables

  • Yellow onions 1 kg

Allergens Gluten, Lactose, Eggs

The recipe, moment by moment

The day beforeWhat's better after resting overnight in the fridge.

  1. Rub the flour with 125 g of cold diced butter and a pinch of salt, add 6 tablespoons of cold water, shape into a ball and wrap it.

    Work quickly with your fingertips, the butter should stay in small flecks for a flaky crust.

  2. Thinly slice the onions and cook them down over low heat with a knob of butter, salt and pepper, covered. 40 min

    Add a splash of water if they stick, they should soften without ever browning.

The same dayDuring the day, whenever you get a moment.

  1. Roll out the dough in a tart pan, prick the base and blind bake it at 180°C. 15 min

    Fill it with dried beans over parchment paper so it doesn't puff up.

  2. Mix the eggs, cream, milk and nutmeg, add the onions, pour over the crust and bake. 35 min

    Pour the filling onto a still warm crust, it won't get soggy and the bottom stays crisp.

When it's time to serveThe final touches, right in front of your guests.

  1. Warm the tart in a low oven before slicing it into portions. 10 min

    Serve it warm rather than piping hot, the nutmeg and onion come through much better.

Our tips to get it right

  • Pick firm yellow onions, their sugar content is ideal for a sweet, mellow filling without any sharpness.
  • Drain the cooked onions briefly before mixing them into the custard if they seem watery, the tart will hold together better.
  • Prick the crust well and use pie weights, otherwise it may puff up and the custard will overflow when you fill it.

The variations

  • Swap part of the heavy cream for fromage blanc for a lighter textured custard, without changing the onion flavor.
  • Add smoked bacon bits cooked with the onions for a richer, more traditional version found in some Alsatian households.
  • For kids, cut the nutmeg in half and slice the tart into small individual pieces that are easier to eat by hand.

What to serve it with

  • A simple green salad with vinaigrette
  • A dry Alsatian white wine
  • A light soup as a starter before

Storage

The tart keeps 2 to 3 days in the fridge in a sealed container. It freezes well once baked and cooled, then reheats in a low oven. Avoid the microwave, which softens the crust.

Questions about this recipe

Can I use store bought shortcrust pastry instead of homemade?

Yes, ready to roll shortcrust pastry works well if you're short on time. The texture will be slightly less flaky, but the tart still turns out well.

Do the onions need to caramelize?

No, actually the opposite. The onions should stay pale and soft, too much browning brings bitterness to the tart.

How do I know the tart is fully baked?

The custard should be set and lightly golden on top, without wobbling in the center when you gently shake the pan. Use 35 minutes at 180°C as a guide.

Can this tart be served as a main dish instead of a starter?

Yes, paired with a generous green salad, it makes a simple full meal. In that case, cut larger portions for 4 people rather than 6.

Can an Alsatian onion tart be made ahead?

Yes, during the day. The recipe needs 40 min of work in total, split up like this, the day before, 2 steps, the same day, 2 steps, when it's time to serve, 1 step.

How long does it take to make an Alsatian onion tart?

Allow 2 h 50 in total, including resting and cooking time, of which 40 min is actual work. The recipe is rated "easy".

How many calories are in an Alsatian onion tart?

About 420 kcal per person, for a recipe meant for 6 people. The calories are calculated by Kiloach, your kilo coach, the app that partners with Mon Chou.

How much does an Alsatian onion tart cost?

About €1.10 per person, that's €6.60 for 6 people, based on average supermarket prices.

What allergens does this recipe contain?

This recipe contains gluten, lactose, eggs. Remember to ask your guests about their allergies before putting your menu together.

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