1. Make the preferment: in a bowl combine your flour, yeast and water. Knead briefly – the dough will be quite firm. Cover with a damp cloth and leave for 11 hours in the fridge or 4 hours in room temperature.
2. The next morning remove the preferment from the fridge, add the water and stir in – or mix in a standing mixer with a dough hook attachment.
3. Add the flour and salt then mix the dough together using your hands or the standing mixer. Add the caraway seeds and knead/mix for 10-15 seconds at 20 minutes intervals for an hour. It should be smooth, stretchy and not sticky.
4. Prepare a Dutch oven, a clay bread baking dish or a round tin or pan about cm diameter by dusting the bottom with semolina. Preheat the oven to 220C/425F/gas 7.
5. Turn the dough out onto a floured work surface. Divide it into 10 equal size pieces. Roll each piece into a ball, place one ball in the centre and then arrange the others tightly around it to make a flower pattern.
6. Cover the rolls with a damp cloth and leave to prove for 45 minutes.
7. If using the cloche or Dutch oven, put the lid in the oven for 30 minutes to heat it up, while the rolls are proving. When they have doubled in size, mix the salt with water for the glaze and brush the tops of the rolls (if using cloche, be careful not to let any water trickle down the sides – it will make the rolls stick to the sides awfully!) and sprinkle with more caraway and black onion seeds.
8. Bake for 40 minutes under the heated cloche lid or in the open pan, until coloured deep golden. Cool in the dish on a wire rack.