Zwiebelkuchen is a seasonal dish that can typically be found in the wine-growing regions of south-west Germany in early autumn. It is the perfect accompaniment to new wine, which is unfiltered grape juice in an early stage of fermentation with an alcohol content ranging from four to 11 percent. New wine, also known as Federweisser (white) or Federroter (red), is only available directly from wine producers and for a few weeks in September and October. This drink is traditionally served and consumed in the popular ‘Besenwirtschaften’, or ‘broom taverns’. These taverns are set up in the barns, garages or even living rooms of wine growers in the autumn, when they are allowed by law to serve their produce without a license for a short period of time. Traditionally, a broom is placed outside the building in order to signal that a tavern is open for business. In addition to wine simple savoury snacks are also served and the Zwiebelkuchen is a firm favourite. I have not been able to source new wine in the UK so far, but the tart also goes very well with a glass of chilled Riesling or a light red, such as a young Pinot Noir. It would probably also team up nicely with a good vintage cider!
The recipe below can be baked in a round form or in a rectangular tin. Choose the size of your tin depending on how deep you would like the onion filling to be. I have used a 32 cm tart form in the photo. The tart is best served warm but it also tastes good reheated on the next day.
For the dough:
20g fresh yeast (or 1 sachet dried)
250 g plain flour (you can also use whole wheat or spelt)
1 pinch sugar
1 tsp salt
50 g butter
150 ml warm water
For the filling:
600 g onions
40 g butter
1 tbsp plain flour
100 ml single cream or crème fraiche
80 g bacon lardons
Dissolve the yeast in the warm water and combine with all the other dough ingredients. Knead for a few minutes until you have a smooth and elastic ball. Leave the dough to rise in a covered bowl until it has doubled in size. Line your greased tin with the dough (not too thick, but not as thin as for pizza).
For the filling chop the onions into small squares. Cook slowly in the butter over a medium heat. The onions should become translucent, but they should not turn brown. It is important to take your time with this – make sure the onions are nice and soft.
When the onions are cooked, stir in the flour and leave to cool slightly. Add the cream and eggs and mix well. Season with salt and with some caraway seeds – make sure you taste the mixture as the onions require quite a lot of salt. Pour the filling into the tin and sprinkle with more caraway seeds and the bacon lardons. Dot with some extra butter, if you like. Bake at 200 degrees for 40-50 minutes.