Vegetarian German Onion Cake (Zwiebelkuchen) Recipe

This vegetarian version of German onion cake, also known as Zwiebelkuchen, is the ultimate comfort food! It’s easily adaptable, outrageously delicious with a perfect consistency, simple to make, and can be prepared in advance. Perfect for feeding a crowd.

Made with a fluffy and moist yeast dough, spread with cream cheese (which makes the cake extra moisture), and then filled with sautéed onions and zucchini. It’s finished off with a cheesy and creamy topping and baked to perfection.

Zwiebelkuchen is a German savory autumn classic loved by both adults and kids. But you don’t have to wait for autumn to enjoy this crowd-pleaser.

It can be made with various types of dough, such as quark-oil dough, shortcrust pastry, or yeast, as in this recipe. Some onion cakes in the Franconian region are even made with sourdough.

The classic onion cake is traditionally made with bacon. However, this version is made with zucchini for my vegetarian husband.

I was proud of the outcome, and my husband loved every bit of it. Since this onion sheet cake was too much for my family and me, we shared some with our family and friends, and they enjoyed it as well.

They even commented on how incredible it is that someone who didn’t grow up with German food makes the best Zwiebelkuchen in the world. What can I say? I have the best teacher in the world – my mother-in-law, Beate.

Ingredients used to make the yeast dough

• 500 g (1.1 lbs/ 4 cups + 2 tablespoons) plain flour (all-purpose flour), plus extra for dusting
• 1 teaspoon sugar
• 80 g (2.6 oz/ ¼ cup + 1 tablespoon) butter, soft
• 300 ml (10.14 fl.oz/ 1¼ cups) milk, lukewarm
• ½ teaspoon salt
• 2 ½ teaspoons dry yeast (7 g/ 1/4 oz )
• 2 tablespoons oil

For the filling

500 g (1.1 lbs) Zucchini

1 kg (2.2 lbs) onions

200 g (7.05 oz) cream cheese

2 tablespoons breadcrumbs

1/2 teaspoon caraway seeds

Salt and freshly ground black pepper to taste

For the topping

• 150 g (5.3 oz/ 1½ cups) grated cheese, mild
• 500 g (1.1 lbs) cream cheese/ sour cream/ schmand
• 2 large eggs
• 1/4 teaspoon nutmeg, ground
• Salt and freshly ground black pepper to taste

How to Make Onion and Zucchini Cake

Put all-purpose flour or plain flour into a large bowl and make a well in the center. Add sugar, yeast, and lukewarm milk to the well. Stir well and let the mixture stand for 10 minutes.

Then, add butter, salt, and oil to the bowl and knead the dough like this:

Using a hand mixer or stand mixer with dough hooks: In a mixing bowl, mix all the ingredients until well combined. Then knead the dough for about 10 minutes (I kneaded the dough for about 7 minutes on low speed (speed 1 on a Bosch kitchen machine) and for an additional 3 minutes at medium-high speed (speed 3)).

• Note: Adjust the kneading time and mixer speed as necessary to achieve a smooth and elastic dough.

By hand: In a mixing bowl, combine all the ingredients together with the help of a fork or similar tool until the flour is well incorporated. Transfer the dough onto a working surface greased with oil and knead with greased hands for about 10 to 12 minutes.

• If you’re using a heavy-duty kitchen machine, please knead your dough for a maximum of 7 minutes in total; otherwise, you will overwork the dough.

Shape the dough into a ball. Cover the bowl with cling film and then with a tea towel. Let it rise in a warm place for about 45 minutes or until the dough has doubled in size.

• If it’s cold where you are, preheat your oven to 50°C (122°F) while making the dough, turn it off, and let the dough rise in the preheated switched-off oven for the indicated time.

Make the filling and bake

In the meantime, peel the onions, slice them, and set them aside. Next, wash the zucchini under running tap water, pat them dry with paper towels, and cut them into cubes.

Heat about 3 tablespoons of oil in a pan over medium heat. Add the zucchini and sauté for about 3 minutes. Then add the onions and sauté for about 10 minutes or until they become translucent. Add caraway seeds and season with salt and pepper. Remove from the heat and set it aside to cool.

In a separate bowl, add cream cheese (or whatever you are using), eggs, and combine them well. Stir in grated cheese, and season with nutmeg, salt, and pepper.

Preheat the oven to 200 degrees with both top and bottom heat. Grease a large baking dish with oil. I used a 45×37 cm (17.72 x 14.57 inch) baking sheet.

Once the dough has doubled in size, place it in the middle of the baking dish. Rub your hands with a few drops of oil and pull out the dough to the size of the baking sheet.

• Alternatively, you could roll out the dough (on a pastry mat with a rolling pin first) into the shape of your baking sheet, then transfer it onto the prepared baking sheet.

Spread the rolled-out dough with cream cheese and sprinkle it with breadcrumbs. Next, transfer the onion-zucchini mixture onto the rolled-out dough spread with cream cheese, evenly.

Then, pour the creamy cheesy mixture all over the top. (Smooth it out with the help of a spoon.) Bake for about 55 minutes or until it’s nicely golden brown.

Let it cool and enjoy. Onion cake tastes great both warm and cold.

Did you make these deliciously German zucchini onion cake? I’d love to hear from you! Simply write a comment and add rating to it.