Icelandic Hot Spring Bread

Instructions

1. Prepare the dough
   In a large bowl, mix the rye flour, all-purpose flour, baking powder, baking soda, salt, and caraway seeds (if using). In a separate bowl, whisk together the golden syrup (or honey), buttermilk, and yogurt until well combined.
2. Mix wet and dry ingredients
   Pour the wet ingredients into the dry ingredients and stir with a wooden spoon until a thick, sticky dough forms. It will be quite dense and heavy – this is normal for rye bread.
3. Prepare the container
   Generously butter a heatproof container with a tight-fitting lid. Traditional Icelandic bakers use milk cartons or special metal containers, but you can use a 2-quart metal coffee can or a heavy loaf pan with foil tightly sealed over the top.
4. Fill and seal the container
   Transfer the dough to the prepared container, filling it only about 2/3 full as the bread will rise during baking. Seal the container tightly to ensure no water can get in during the baking process.
5. Traditional geothermal baking
   If you're in Iceland near a geothermal area, bury the sealed container in hot sand near a hot spring where the temperature is around 212°F (100°C). Let it bake for 24 hours. For home cooking, preheat your oven to 200°F (95°C) and place the container in a large roasting pan filled with water halfway up the sides of your bread container to create a water bath.
6. Bake slowly
   Bake the bread in the water bath at 200°F for 8-12 hours (overnight works well). The low temperature and long cooking time are essential for developing the characteristic dark color and sweet flavor.
7. Cool and slice
   Once baked, remove from the oven and let cool completely before removing from the container. The bread should be dark brown, dense and slightly sweet. Slice thinly for serving.
8. Serve traditionally
   Serve slices with a generous spread of butter. In Iceland, it's often topped with smoked salmon, smoked lamb (hangikjöt), or cheese. The bread stays fresh for several days and gets better with time.