Zwiebelkuchen (Onion Cake)

Where I come from in Germany, Zwiebelkuchen (onion cake, onion pie or onion tart) is a typical early fall specialty. It is made of sautéed onions with cream, egg and bacon on a rich yeast dough crust. It is usually served with Neuer Wein ("new wine"), also known as Federweißer.

This is my mother's recipe for Zwiebelkuchen. In the notes section is my adaptation of the recipe to use a sourdough starter instead of commercial yeast.

If no Federweißer is available, serve with a fruity but dry Riesling.

Ingredients

For the crust

• 1 lb 8 oz / 600 g flour
• 5 tbsp / 75 g butter, melted
• 1 egg
• 1 packet of active dry yeast (see notes for my sourdough version)
• 1 tsp salt
• 1 tsp sugar
• ½ cup / 120 ml water
• ½ cup / 120 ml milk
• 2 tbsp butter for the pans

For the topping

• 3 lb / 1.5 kg onions, sliced or coarsely chopped
• 1 tbsp butter
• 1 tbsp vegetable oil
• 1 tsp salt
• 2 tsp caraway seeds
• ½ - 1 tsp freshly ground pepper
• ½ cup dry white wine
• 1 cup / 250 ml heavy whipping cream
• ½ cup / 125 ml sour cream
• 5 eggs
• 4 oz / 125 g bacon, diced
• 4 stalks of green onions, chopped
• ½ cup / 125 ml milk
• ½ tsp white pepper, freshly ground
• ½ tsp salt
• ¼ tsp nutmeg, freshly grated
• pinch of cayenne pepper
• 2 tbsp parsley, chopped

Preparation

Dough for the crust

1. Dissolve yeast in half of the milk.
2. Combine flour, yeast (or sourdough starter), 1 egg, sugar, salt, milk, milk with yeast, water and melted butter. Knead until the dough is smooth and elastic.
3. Form a ball, coat thinly with oil and let rise in a warm place until volume has about doubled.

Topping

1. Meanwhile, heat butter and oil in a large heavy pan over high heat. Add caraway seeds. Add onions, 1 tsp salt and 1 tsp of pepper. Cook for about 15 minutes, stirring frequently and making sure the onions don't brown (turn down heat if necessary).
2. Add wine and cook for another 10 minutes until the liquid has evaporated. Set aside.
3. Whisk together cream, sour cream, milk, eggs, pepper, nutmeg and salt. Add cayenne pepper and stir in chopped parsley. Set aside.

The Onion Cakes

1. Generously butter 2 large pizza pans, 1 tbsp of butter per pan.
2. Preheat oven to 375°F / 190°C.
3. Divide dough into two equal parts. Stretch or roll out each part and put on a pizza pan. Spray with a bit of water or cover with a damp cloth and let rise for another 15 minutes.
4. Top each pan with half of the onions, pour half of the egg-cream mixture on top and add the green onions and bacon.
5. Bake for about 30 minutes until the crust is golden brown and the egg mixture has set. (It is easiest to bake both pans at the same time in a convection oven; alternatively, swap the pans from time to time between upper and lower rack.)

Notes

Sourdough Version

1. In a mixing bowl combine 4½ oz / 140 g all-purpose flour with 4½ fl oz / 140 ml water. Add 1 tbsp of sourdough starter culture. Cover and let stand overnight in a not too cold place until very bubbly.
2. Follow the recipe using 1 lb ½ oz / 460 g of flour, no water (only milk) and omitting the yeast.

Meatless Version

• Omit the bacon or replace it with 2 additional chopped stalks of onion greens.

Yields 6-8 servings

Preparation time about 1½ - 2 hours