To make the bread, preheat the oven to 240C/220C F/ Gas 9. Put a baking sheet on the top shelf of the oven.
Sift the flour, salt and bicarbonate of soda into a large bowl. Add the rosemary and spring onions. Make a well in the centre of the flour and pour in the buttermilk, gently mixing everything together with a spatula or large round-edged knife. Stir in 55ml cold water until you have a soft dough. It should be neither too dry nor too sticky – add 1-2tbsp more water if it feels dry.
Remove the baking sheet from the oven and dust it liberally with flour. Turn the dough out on to the baking sheet. Pat it into a round shape about 15cm wide. Press a deep cross on top with a floured wooden spoon or knife and prick each quarter. Dust the top with more flour.
Turn the oven down to 220C/200C F/Gas 7 and bake the dough on the top shelf for 30-35 minutes until lightly browned and hollowsounding when tapped underneath. Remove and transfer to a wire rack to cool.
Crack the crab claws so the meat can be easily removed. Cover and put in the fridge.
Put the dulse in a small bowl and cover with cold water. Put the butter, oil, ginger, spring onions, garlic, lemon zest and juice and chilli in a small frying pan set over a medium heat. Simmer for 1 minute, then set aside to keep warm and infuse.
Drain the dulse, squeeze out excess moisture, roughly chop and add to the butter mixture. Serve the crab with the flavoured butter and bread.
Recipes and photography taken from The Irish Kitchen by Cherie Denham, photography by Andrew Montgomery (Montgomery Press, £30)
