For the sunflower bread, mix the flour with the salt in a bowl. Make a small depression in the center and crumble the yeast into it, sprinkle with sugar and mix the yeast with a little warm water. Cover and let rise in a warm place for about 15 minutes.
Add the sourdough and the remaining water and knead with the dough hook of the food processor for about 5 minutes. Now let the dough rise for another 30 minutes. Add the sunflower seeds and knead the dough thoroughly again.
Put the finished dough into 2 loaf pans and let rise for another 30 minutes. Brush the loaves with a little water and top with sunflower seeds, pressing them slightly into the dough.
Preheat the oven to 240 °C and bake the loaves in it for 10 minutes , then reduce to 200 °C and bake for another 45- 50 minutes. Remove the loaves and let them cool on a cooling rack.