Roughly chop the walnuts. Put all types of flour in a food processor and mix with salt, sunflower seeds, chopped walnuts and bread spices using a mixer / kneading attachment. In the meantime, dissolve the yeast in water, add vinegar and add to the flour mixture while turning, mix on a high level for about 1 minute.
In the meantime, oil the Römertopf and sprinkle with coriander seeds. Put the dough in the Römertopf, smooth the surface with damp hands and sprinkle with the remaining coriander and sunflower seeds. Immediately place the pot in the non-preheated oven and bake at 200 degrees Celsius for 1 hour 15 minutes. Then let it cool down for about 30 minutes.