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1
Make the dough and let it rise
10 Mins + 60 Mins rise
Warm milk, about 37°C (98°F)
Stir the yeast and sugar into the warm milk and melted butter and rest for 10 minutes until foamy. Tip the flour and 4g of the salt into a large bowl, add the yeasted milk and 1 beaten egg, and mix into a soft dough. Knead on a floured surface for 10 minutes until smooth and elastic, then put it in an oiled bowl, cover, and leave in a warm place for 1 hour until doubled in size.
The milk must feel just warm on your wrist — hotter than 43°C (110°F) kills the yeast and the dough will never rise.
Done when: The dough is smooth, springy, and twice its original size.
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2
Cook the onions slowly
15 Mins
Medium heat, about 160°C (320°F)
Melt the remaining 20g of butter in a large pan over medium heat. Add the sliced onions and the caraway seeds with a pinch of salt and cook, stirring often, for about 15 minutes until the onions are soft, golden and sweet. Take the pan off the heat and let the onions cool for 10 minutes so they do not scramble the eggs.
If the onions start to catch, add a splash of water and turn the heat down — browned onions are good, burnt ones are bitter.
Done when: Onions soft, golden and sweet-smelling, with no liquid left in the pan.
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3
Line the tin and fill it
10 Mins
Room temperature, about 20°C (68°F)
Heat the oven to 190°C (375°F) and butter a 28 cm round tin or a 30 x 20 cm tray. Knock the dough back, roll it out, and press it into the tin, building the sides about 3 cm high. Spread the cooled onions evenly over the base. Whisk the sour cream with the 2 beaten eggs, the remaining salt, nutmeg and pepper, pour it over the onions, and scatter the grated Emmental on top.
Press the dough up the sides — it holds the custard in while it bakes.
Done when: The tin is lined, the onions are covered with custard, and the cheese is scattered evenly.
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4
Bake until deep golden
35 Mins
190°C (375°F)
Bake on the lowest oven rack for 30 to 35 minutes until the crust is deep golden and the filling is set and lightly browned on top. A knife pushed into the centre should come out clean, with no runny custard clinging to it.
If the top browns too fast, lay a sheet of foil loosely over it for the last 10 minutes.
Done when: Deep golden crust, filling set and lightly browned, and the centre firm when tested.
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5
Rest, then slice
10 Mins
Room temperature, about 20°C (68°F)
Leave the cake in its tin for 10 minutes so the filling firms up, then lift it out and cut into 8 slices. Serve warm, or at room temperature.
Cutting it straight from the oven makes the filling run — 10 minutes of patience gives clean slices.
Done when: The cake holds its shape when sliced, with a golden base and a creamy onion filling.
auto_awesome Finishing Touches & Plating
Serve the slices warm from the tin, with a green salad alongside and Federweisser or dry Riesling in the glass — that is how the wine festivals eat it.
Germany
3h 30m
