Crustless onion tart

Ingredients

• 500 g (about 4)onions
• 1 tablespoon (about 15 ml)butter or oil
• 4 mediumeggs
• 170 mlmilk
• 130 gplain flour
• 200 gBergkäse, diced or grated
• 150 gdiced smoked ham or bacon (optional)
• to tastesalt
• to tasteblack pepper

Instructions

1. 1

   Cook the onions

   Peel and finely chop the onions. Soften them in a little oil or butter, then add the ham or bacon at the end. Set the mixture aside.

2. 2

   Prepare the tin

   Heat the oven to 175°C, using conventional top and bottom heat. Line the base of a springform tin with baking paper, lightly grease the sides and dust them with flour. Beat the eggs well, then stir in the milk.

3. 3

   Mix the filling

   Sift the flour into the egg mixture and stir it in. Add the grated or diced cheese and the onion and ham mixture. Season with salt and pepper to taste.

4. 4

   Bake the tart

   Transfer the mixture to the tin and bake the onion tart for about 35–40 minutes.

What is a crustless onion tart?

This is a pastry-free take on German-style Zwiebelkuchen, a savoury onion bake often made with a dough base. Here, eggs, milk and flour hold the onions and cheese together in a tender, sliceable filling.

Bergkäse brings a full, savoury flavour, while the optional smoked ham or bacon adds another layer of richness. The simple batter makes this version quicker to assemble than a tart with yeast dough.

Nutrition and macros by portion

The nutrition label shows one serving as written: 180 calories, 10g protein, 11g carbs, 11g fat.

The flour supplies most of the carbohydrates, while the eggs and cheese contribute protein. Much of the fat comes from the cheese, eggs and butter or oil, with smoked ham or bacon adding more if used. Pair a slice with a generous salad or other vegetables to round out the plate.

Soften the onions first

Onions: chop them finely so they soften evenly and are easy to portion through the tart. Cook them gently in the butter or oil until softened rather than rushing them over high heat.

Ham or bacon: add it towards the end of cooking, as the method directs. Set the mixture aside while you prepare the batter.

Choose and prepare the cheese

Bergkäse: its robust flavour suits the sweetness of cooked onions. Grated cheese disperses evenly through the mixture, while small cubes make more distinct pockets.

Either form works in this recipe, so choose according to the texture you prefer. If using cubes, keep them small enough to distribute throughout the batter.

Mix a smooth batter

Eggs and milk: beat the eggs well before stirring in the milk, as this helps form an even base. Sifting in the flour makes it easier to incorporate without leaving lumps.

Add-ins: stir in the cheese and onion mixture once the flour is combined. Season at this stage, bearing in mind that smoked ham or bacon and Bergkäse can already be quite savoury.

Check the bake

Oven: use conventional top and bottom heat at 175°C. Lining the base and greasing and flouring the sides helps the baked tart release from the springform tin.

Doneness: bake for 35–40 minutes, as directed. The exact time may vary with the tin and oven, so check that the centre has set before taking it out.

Serve it simply

This tart can be served warm or allowed to cool until just warm, when it is easier to cut into neat portions. A crisp green salad makes a fresh contrast to the soft, cheesy filling.

For a more substantial meal, serve it with boiled potatoes or a bowl of soup. Keep accompaniments simple so the onion and Bergkäse remain the focus.

Recipe notes & tips

• Chop the onions finely so they soften evenly.
• Grate the Bergkäse for an even distribution, or dice it small for pockets of cheese.
• Let the onion mixture cool briefly before mixing it into the eggs.
• Season carefully if using smoked ham or bacon, as these and the cheese can be salty.
• Line the base of the springform tin and grease and flour its sides to help release the tart.

Variations

• Leave out the meat: omit the optional ham or bacon for a meat-free tart.
• Use oil: replace the butter with oil to soften the onions.
• Try a different cheese: use another firm, flavourful cheese in place of Bergkäse.
• Change the texture: use grated cheese for an even mix or small cubes for distinct bites.
• Serve with salad: add a crisp green salad for a fresh contrast.

Common mistakes to avoid

• Large onion pieces: chop them finely so they soften and distribute evenly.
• Rushing the onions: cook them gently until softened before adding the optional ham or bacon.
• Lumpy batter: sift in the flour and stir it into the egg mixture thoroughly.
• Over-seasoning: taste and season with restraint if your cheese or smoked meat is salty.
• Removing it too soon: bake for 35–40 minutes and check that the centre has set.

How to store

Once cooled, cover and refrigerate leftovers for up to 3 days. Reheat portions in the oven until warmed through, or serve them cold or at room temperature.

Frequently asked questions