When the grapes are harvested in Pfalz and Baden, Zwiebelkuchen, the German onion tart, is on the table all over south-west Germany: a thin yeast-dough base under a thick layer of onions, steamed soft and sweet without taking on colour and held together by a creamy egg custard with bacon and caraway. If you bake Zwiebelkuchen in the air fryer, you can enjoy the same autumn classic at home.
Advertisement: The page displays ads and contains advertising links (affiliate links). See our advertisers here.
The tart is traditionally eaten warm with Federweißer, the young, partially fermented grape must from the German wine regions. Here you get my experience from the kitchen, the mistakes I have made myself, and the full recipe at the bottom of the page.
Estimated reading time: 4 minutes
Table of Contents
Why I love Zwiebelkuchen in the air fryer
Zwiebelkuchen shows how a few cheap ingredients can become something festive. A full 700 g of yellow onions cook down under the lid into a soft, sweet mass; caraway and nutmeg give it its warm, spiced flavour, and the bacon adds salt and richness, while the eggs and crème fraîche bind the filling.
A 20-22 cm springform pan fits in most larger air fryers, so you do not have to heat up the oven for a single tart. The circulating hot air also gives a lovely, golden surface.
The difference between Zwiebelkuchen, Flammkuchen and quiche Lorraine
Flammkuchen from Alsace has a paper-thin, crisp base with a thin layer of crème fraîche, onions and bacon, and is baked briefly at high heat. Quiche Lorraine has a shortcrust base and a filling of egg, cream and bacon. Zwiebelkuchen is something else entirely: a soft yeast base with a small rim and a filling that is first and foremost onions, only just held together by egg and soured cream.
My kitchen test of Zwiebelkuchen
I tested the Zwiebelkuchen in my Cosori Dual Blaze, which has heating elements both at the top and at the bottom of the basket, so the yeast base gets heat from below while the filling bakes from above. I blind-bake the base for 5 minutes at 180 °C so it sets. Then I spread out the onion filling and keep baking for 30 minutes at 160 °C, until the filling has set and turned golden. The moderate temperature is deliberate, because at a higher heat the surface turns dark before the middle has set. I still turn the pan half a turn after 15 minutes so the colour is even.
The whole process takes 120 minutes: 40 minutes of preparation, 45 minutes of rising time and 35 minutes in the air fryer. The onions are steamed and cool down while the dough rises. Finally, I stick a knife into the filling. It should come out clean, and the middle may wobble only slightly; otherwise the tart gets 3-5 minutes more at 160 °C. If the top gets too dark, I lay aluminum foil over it and fold it tightly down around the pan so it cannot be blown up into the heating element.
Let the onions cool completely before they go into the egg mixture. Warm onions make the eggs set too early, and then the yeast base turns soft instead of baking through.
Tips and tricks from the author: Morten Jensen
The typical mistakes and how to avoid them
The first mistake is to fry the onions instead of steaming them. If they take on colour, the flavour turns roasted and strong instead of mild and sweet, so keep the heat low, put the lid on, and stir regularly until the onions are soft and glossy. The second mistake is being in a hurry with the cooling. If the onions go into the egg mixture while still warm, it starts to set before the tart is in the basket, and the base turns soggy. Spread the onions out on a shallow dish, and they cool faster. The third mistake is skipping the blind-baking. Without those 5 minutes at 180 °C, the yeast dough does not get the chance to set under the heavy filling, and the base turns doughy. Prick it well with a fork first so it does not bubble up.
How to serve Zwiebelkuchen
Let the tart rest for 10 minutes before you loosen the edge, so the filling settles. Then serve it like this:
- Classic, with Federweißer, the young, partially fermented grape must from Pfalz and Baden
- With a dry Riesling or apple juice if you cannot get hold of Federweißer
- With a green salad in a tangy vinaigrette that balances the richness of the bacon and eggs
- Cut into 8 smaller pieces to go with a glass of wine when guests come over
Storage and reheating
Leftover Zwiebelkuchen keeps covered in the fridge for up to 3 days. Reheat the pieces in the air fryer at 160 °C for 3-5 minutes so the base gets its bite back, whereas the microwave often makes it soft. The tart can also be frozen for up to 3 months. Let it thaw in the fridge overnight before you heat it.
Zwiebelkuchen is proof of how much flavour hides in ordinary yellow onions. Bake it on an autumn weekend when there is time for the rising, and enjoy it warm with a glass of Federweißer or white wine.
FAQ
Schmand is a German soured cream with about 24% fat, which is hard to find in Denmark. Crème fraîche with 18% fat is the easiest substitute and gives the same fresh tanginess.
A 20-22 cm springform pan fits in most air fryers of 5.5 litres and above, but always measure the basket first. If you have a smaller air fryer, you can bake in two small pans one after the other and check the filling after 25 minutes.
Recipe
Zwiebelkuchen in the Air Fryer
Cooking Guide
Keep the screen on and follow the recipe step by step while you cook.
Step 1:
Avoid the screen turning off while you cook.
Step 2:
Start the guide and follow the recipe one step at a time.
Cost of the dish
Prices may vary depending on where you shop.
Our estimate is based on average food prices for the current year 2026.
Estimated price for the whole dish:
Airfryer size
All our recipes are tested in a Philips Airfryer 2000 Series NA230/00 – 6.2 L
Does the recipe fit my Airfryer?
If you’re unsure, you can always reduce by one serving in the recipe, or click the 0.5x button.
You can also Ask the AI Chef
It’s easy! Just press the Ask the AI Chef button you see at the bottom.
Recommended equipment
- 1 Air fryer
- 1 Springform pan (20-22 cm) - must fit in the basket
- 1 Cutting board
- 1 Chefs knife
- 1 Large pot with lid
- 1 Wooden spoon
- 1 Shallow dish
- 1 Mixing bowl
- 1 Bowl
- 1 Whisk
- 1 Kitchen towel
- 1 Rolling pin
- 1 Parchment paper
- 1 Aluminum foil
- 1 Oven mitts
Shopping list
Ingredients
- 700 g onions (yellow, cut into thin half rings)
- 100 g bacon (cut into small cubes)
- 1 tbsp butter (for the onions)
- 3 pcs eggs
- 200 g crème fraîche (18% fat, instead of Schmand)
- 1 tsp caraway seeds (whole)
- 0.5 tsp salt
- 0.5 tsp black pepper (freshly ground)
- 1 pinch nutmeg (grated)
How to make it
Yeast dough
- Warm 1 dl milk until it is lukewarm (about 37 °C), and dissolve 10 g yeast in it.
- Cover the bowl with a kitchen towel, and let the dough rise in a warm place for 45 minutes, until it is clearly bigger. Make the onion filling in the meantime.
Onion filling
- Peel and halve 700 g onions, and cut them into thin half rings of about 3 mm.
- Sauté 100 g bacon in a large pot over medium heat for 3-4 minutes, until the fat renders out. The bacon should not turn crisp.
- Turn down to low heat, and add 1 tbsp butter and the onions. Put the lid on, and steam the onions for 15-20 minutes, stirring occasionally, until they are completely soft and glossy but without colour. Take the lid off for the last 3-4 minutes so the moisture evaporates.
- Season the onions with 1 tsp caraway seeds, 0.5 tsp salt, 0.5 tsp black pepper and 1 pinch nutmeg.
- Spread the onions out on a shallow dish, and let them cool completely while the dough finishes rising. Warm onions make the eggs set too early and turn the yeast base soft.
- Whisk 3 pcs eggs and 200 g crème fraîche together in a bowl, and fold in the cooled onions.
Cooking in the air fryer
- Line the base of the springform pan with parchment paper, and grease the sides lightly.
- Knock back the dough, and roll it out on a floured surface into a thin, round sheet that is about 6 cm wider than the pan. Lay it in the pan, and press it up the sides so there is a rim of about 3 cm.
- Prick the base well with a fork, and let it rest for 10 minutes.
- Preheat the air fryer to 180 °C fan.
- Place the pan in the basket, and blind-bake the base for 5 minutes at 180 °C, so it sets and does not turn soft under the filling.
- Pull out the basket, and spread the onion filling evenly in the blind-baked base.
- Turn down to 160 °C, and bake for 30 minutes, until the filling has set and is golden on top. Turn the pan half a turn after 15 minutes. If the surface gets too dark, lay aluminum foil over it, and fold it tightly down around the pan so it cannot be blown up into the heating element.
- Check that the filling has set: it should wobble only slightly in the middle, and a knife inserted into the filling should come out clean. If not, bake for 3-5 minutes more at 160 °C.
Serving
- Lift the pan out with oven mitts, and let the tart stand for 10 minutes so the filling settles before you loosen the edge.
- Cut the tart into 4 pieces, and serve it warm with Federweißer or a glass of dry white wine and a green salad on the side.
Our notes for the recipe
Steam the onions under a lid over low heat so they turn soft and sweet without taking on colour, and let them cool completely before they go into the egg mixture. Warm onions make the eggs set too early and turn the yeast base soft. Blind-baking makes sure the base bakes through under the wet filling. The filling is done when it wobbles only slightly in the middle – it sets completely while the tart rests. Variation:
In south-west Germany they use Schmand, a soured cream of about 24% fat, which is replaced here with 18% crème fraîche. For a vegetarian version, leave out the bacon and steam the onions in 2 tbsp butter. If you are not a fan of caraway, you can leave it out, but it is part of the classic flavour. Serving:
Zwiebelkuchen is eaten warm in the autumn together with Federweißer, a young, partially fermented grape must that is sold in the wine regions of Pfalz and Baden at harvest time. If you cannot get hold of it, a dry Riesling or apple juice works nicely, and a green salad with a tangy vinaigrette completes the meal. Portion size:
The tart makes 4 large lunch portions or 8 smaller pieces to serve with a glass of wine. A springform pan of 20-22 cm fits in most air fryers of 5.5 litres and above, so measure the basket first. If your air fryer is smaller, you can bake in two small pans one after the other and check the filling after 25 minutes.
Your notes for the recipe
Nutrition per serving (Guideline)
Important about shelf life and nutrition
Nutrition per serving (guideline): Calculations are based on data from the United States Department of Agriculture (USDA). Shelf life (guideline): Shelf life data is provided, as far as possible, by public institutions, including national food authorities. Our information is therefore only indicative, and it is your responsibility to obtain and calculate accurate information about shelf life and nutrition for all recipes on airfryerkogebogen.dk
Easily share the recipe with others:
Via email or on Facebook
Open the recipe on your phone
Scan the QR code with your phone and get the recipe directly on your mobile while you cook.
Author
Airfryerkogebogen.dk
