Swabian Zwiebelkuchen (Onion Cake)

Preparation time approx. 3.5-4 hours
You should definitely serve a Federroter (red must) or Federweisser (white must) with this!

Preparation You'll need: A medium springform pan (approx. 21 x 7 cm) A medium pan A medium bowl
Ingredients Dough (for 2 persons) 20+50 g wholemeal flour 20+50 g spelt flour ½ tsp. salt ½ tsp. sugar 10 g yeast 50+25 mL milk 25 g butter
Ingredients Topping (for 2 persons) 250 g chopped onions (2-3 pieces) 25 g butter 1 Tbsp. flour (you can use standard flour here, I usually use spelt or wholemeal, the package is already standing around ;-) 1 egg (L) 200 g sour cream A few pinches of salt 1 tsp. caraway seeds 50-60 g smoked bacon, diced
The Sponge Put 20 g each of wholemeal and spelt flour into the mixing bowl, add 10 g yeast (crumbled), 50 mL milk and 1/2 tsp sugar. Mix everything well and place in the oven. Heat the oven to 30℃ and turn it off again immediately. Allow the pre-dough to work until the volume has doubled (approx. half an hour). Put out 2x 25 g butter so that it is not so cold.
Make the dough As soon as the volume of the pre-dough has doubled, add 50 g each of wholemeal and spelt flour, as well as 25 mL milk, 1/2 tsp salt, 25 g butter. (Let) knead for 7-10 minutes. Then place the bowl back in the oven, covered, and bring back up to 30℃ and turn off. The dough should rest for at least 2 hours! After 1 hour, you could take care of the topping....
The Topping Finely chop 2-3 onions (250 g are needed). Sauté with 25 g butter in a medium frying pan over a good medium heat until translucent (approx. 5-7 minutes), turn off. Then sprinkle with 1 Tbsp flour, mix well and leave to cool. In a medium bowl, whisk 200 g sour cream and 1 egg (L). Add a few pinches of salt, 50 g smoked bacon cubes and 1 tsp caraway seeds (whole). Mix well again and also put aside.
Make the cake After the dough has rested, roll it out so that it fits well in the small springform pan. Spread into the tin; the dough should reach almost all the way to the top. Preheat the oven to 200°C (top/bottom heat). Now add the onion mass to the sour cream in the bowl and mix everything well. Pour into the cake tin and sprinkle with a little caraway and (if you like) a little diced bacon. Don't be surprised, the topping is only about half as high as the edge of the pastry (this rises significantly during baking). Bake the cake for about 40 minutes (until topping is getting light brown), then leave to cool for another 5 minutes and serve warm with new wine.