Dissolve the yeast and sugar beet syrup in the lukewarm beer.
Mix both flours in a bowl, add the sourdough and oat flakes and knead with the food processor on the lowest setting for about 5 minutes.
Then add the salt and knead for another 4 - 6 minutes.
While kneading, add the mashed bananas tablespoon at a time. If the dough is too sticky, add a little more wheat flour. The dough should come off the edge of the bowl and have a soft consistency. Now put the dough in a large, oiled bowl and cover and let rise in a warm place for about 45 minutes.
Now knead the dough briefly on a floured work surface, shape it into a round shape and cover it in a floured bowl or proving basket and let it rest for about 1 hour in a warm place.
Meanwhile, heat up the oven with the pot or Dutch oven to 250 ° C - this takes about 45 minutes.
Let the dough slide into the Dutch oven, cover with the lid and bake for 15 minutes. Then lower the temperature to 210 ° C and bake the bread in about 35 - 45 minutes. Then take the bread out of the pan and leave it in the switched-off oven with the door slightly open for another 10 minutes.
Now just let it cool down on a wire rack and enjoy.