Mix rye flour, wheat flour, 1 tablespoon sugar, 2 teaspoons salt, dried yeast and sourdough extract in a bowl. Add 450-500 ml lukewarm water and knead everything with your hands (or food processor) for 5-7 minutes to a smooth dough.
Cover and leave to rise in a warm place for about 45 minutes.
In the meantime, dice the bacon. Peel and chop the onions. Heat oil in a pan. Fry the bacon in it. Sprinkle with 2 tablespoons of sugar and caramelize lightly. Add onions and fry for 2-3 minutes.
Take out and let it cool down.
Knead the onion mixture into the dough. Form an oblong loaf of bread, possibly turning it in rye meal or flour. Sprinkle a baking tray with water. Place baking paper on top and sprinkle the baking paper with water as well.
Place the loaf on top, cover and leave to rise for about 20 minutes.
Cut the top of the bread several times at an angle with a sharp knife. Bake in the preheated oven (electric cooker: 250 °C/circulating air: 225 °C/gas: see manufacturer) for approx. 15 minutes. Turn down the oven temperature (electric oven: 200 °C/circulating air: 175 °C/gas: see manufacturer).
manufacturer) and continue baking for 15-20 minutes. Let the bread cool down.