Onion Tarte Tatin

Lunch

Sweet caramelized onions under crisp buttery pastry, flipped upside down so the glossy, sticky onions become the top. The honey and balsamic create a dark, savoury-sweet glaze. Brilliant with a green salad and a glass of red wine!

Pin recipe Print

Prep Time 20 minutes mins

Cook Time 1 hour hr

Total Time 1 hour hr 20 minutes mins

Servings 4

Ingredients 

1x2x3x?

For the caramelized onions

• 1 kg onions yellow, red, or sweet
• 30 gr unsalted butter
• 2 tbsp honey
• 50 ml balsamic vinegar
• 100 ml water
• few sprigs thyme
• salt and black pepper

For the pastry

• 250 gr plain flour
• 125 gr unsalted butter cold
• 60 ml water
• pinch salt
• 1 egg yolk, optional

Equipment

cast iron skillet

food processor

rolling pin

knife

wooden spoon

plate larger than your pan

Instructions

Make the pâte brisée

• Put the flour and salt in a large bowl. Add the cold butter cubes and rub them in with your fingertips until the mixture looks like breadcrumbs. Work quickly.

  Mix the egg yolk (if using) with 50ml cold water. Pour over the flour mixture and bring together into a dough. Add more water if needed, but don't make it sticky.

  Shape into a flat disc, wrap in cling film, and refrigerate for at least 30 minutes.

Caramelize the onions

• Peel the onions and cut them in half across the middle (horizontally).

  Melt the butter in your ovenproof skillet over medium heat. Add the honey and stir until it melts into the butter.

  Arrange the onion rounds in the pan, cut-side down. Pack them in tightly as they'll shrink as they cook.

  Pour in the balsamic vinegar and water. Tuck the thyme sprigs between the onions. Season with salt and pepper.

  Cook over medium-low heat for 30-40 minutes. Don't cover. The liquid should reduce to a thick, sticky glaze and the onions should be very soft and caramelized.

  The onions are ready when they're soft enough to squash easily, deeply caramelized, and sitting in just a little sticky glaze.

Assemble and bake

• Preheat your oven to 180°C (160°C fan).

  Remove the thyme sprigs. Roll out the pastry on a lightly floured surface to about 3mm thick. Cut a circle 2-3cm larger than your pan.

  Lay the pastry over the onions, tucking the edges down inside the pan around the sides. Prick the pastry a few times with a fork.

  Bake for 25-30 minutes until the pastry is golden brown and cooked through.

Flip and serve

• Take the pan out of the oven. Let it sit for 5 minutes, no longer or the caramel will set.

  Place a large serving plate over the pan. Using oven gloves, hold the plate and pan firmly together and flip the whole thing over in one quick, confident movement.

  Lift the pan off carefully. The onions should be sitting with their caramelized rings facing up, glossy and beautiful.

  Serve warm or at room temperature, cut into wedges.

Notes

• Yellow onions are classic, they caramelize beautifully. Red onions add colour and are slightly sweeter. Sweet onions like Roscoff or Vidalia need less sugar. Shallots work too, though you’ll need more of them.
• Use a light, mild honey like acacia or wildflower. Strong honeys like chestnut can overpower the dish. The honey creates a glossy glaze and adds subtle sweetness that balances the balsamic’s acidity.
• You want just enough sticky glaze to coat the onions, not a watery sauce. If there’s too much liquid, reduce it before adding the pastry.
• Pâte brisée is traditional and holds up better than puff pastry. You can use shop-bought if you’re short on time.

About this recipe

Yes, another tarte tatin recipe. Because once you’ve tasted one, you really can’t get enough of them. This time we’re making an onion tarte tatin, the savoury cousin of the famous apple tarte tatin. Same technique but with a different filling. You cook the filling in the pan, then cover it with pastry, stick it in the oven and bake it, and at last flip the whole tart to reveal what you’ve created. Those caramelised onions on top of this upside down onion tart look impressive every single time. And the best part? It’s actually much simpler than it sounds.

Where the tarte tatin format comes from

The classic apple tarte tatin was supposedly invented by accident in the 1880s at the Hôtel Tatin in Lamotte-Beuvron. The story goes that the original tarte tatin was something like an apple tart. But one day, Stéphanie was overwhelmed during a busy service, put the apples in the pan with butter and sugar but forgot the pastry, and improvised by adding it on top and returning the whole thing to the oven. When she flipped it, the caramelised apples were back on top. She served it, and customers loved it.

The savoury caramelised onion tarte tatin is considerably more recent, probably from the 1980s and 90s when French chefs started applying the tarte tatin format to vegetables. Onions, leeks, tomatoes, chicory, beetroot. Anything that caramelises well works beautifully. And this version keeps it wonderfully simple: onions, butter, sugar, vinegar, thyme. The format does the rest.

Why onions work so well

The honey helps the onions caramelise and creates that sticky glaze that makes this tart look as good as it tastes. The vinegar adds just enough sharpness to balance the sweetness. The French butter makes everything rich. It’s a small ingredient list that does a lot of work.

Yellow onions are the standard choice to make this french onion tarte tatin: the right balance of sweetness and sharpness. Red onions are sweeter and add beautiful colour. And if you can find Roscoff onions from Brittany or Cévennes onions from the south, those are the traditional French choices and they need very little added honey. Shallots work too and give a more refined flavour, though you will need quite a few of them.

The one thing you really can’t rush

The technique here is entirely about patience. You simply cannot rush caramelised onions, they need time to break down, release their sugars, and turn sweet and soft. If you cook them too fast, they will burn on the outside while staying raw in the middle. So put your heat to low, use enough butter, and wait to cook them properly. That really is the whole method. Put on some music, pour yourself a glass of something nice, and let them do their thing.

The flip

The flip is the moment of truth with any tarte tatin, and I won’t pretend it isn’t a little nerve-wracking the first time. Let the tart rest for five minutes after it comes out of the oven so the caramel thickens slightly but hasn’t set completely. If you flip too soon, which I have done many times, everything slides off. If you do it too late, everything sticks to the pan. Get a plate bigger than your pan, hold everything firmly, and flip in one confident movement. Don’t hesitate, that’s what causes disasters.

The right pan

A caramelised onion tarte tatin needs a pan that goes from hob to oven, distributes heat evenly during that long caramelisation stage, and releases the tart cleanly when you flip it. This is exactly where a good cast iron skillet earns its place in your kitchen.

I recommend using the Staub cast iron skillet for this upside down onion tart. The heavy base distributes heat evenly during the slow caramelisation on the hob, so no hot spots and no burnt patches. It goes straight from hob to oven without any issue. And the black enamel interior gives you excellent caramelisation without sticking, which matters enormously when you’re about to flip the whole thing upside down onto a plate. I won’t lie, it’s a heavy pan to flip, but if you can get the hang of it, you won’t be disappointed with the results.

How to serve it

This caramelized onion tarte tatin works beautifully as a starter, a light main course, or cut in half as a main course. The onion tarte tatin taste better at room temperature than piping hot. The flavours come through so much more clearly once the tart has had a few minutes to settle. Serve it with a simple green salad dressed with mustard vinaigrette. The bitter leaves cut through the sweetness of the onions perfectly. And of course a nice glass of red wine like a Côtes du Rhône alongside. That’s really all you need.