Icelandic Thunder Bread

Instructions

1. Prepare the dry ingredients
   In a large mixing bowl, combine the rye flour, all-purpose flour, baking powder, baking soda, and salt. Whisk together until thoroughly mixed.
2. Add the wet ingredients
   Add the brown sugar to the dry ingredients and mix well. Pour in the buttermilk and golden syrup or molasses. Stir until you have a smooth, thick batter with no dry pockets of flour.
3. Prepare the baking container
   Thoroughly grease a large, heatproof container with a tight-fitting lid. Traditional recipes use a milk carton or similar container. The container should be filled only 3/4 full as the bread will rise during baking.
4. Pour and seal
   Pour the batter into the prepared container and seal tightly. If using the traditional geothermal method, the container must be completely watertight.
5. Bake the bread
   For oven baking: Place the container in a large, deep baking dish filled with hot water that comes halfway up the sides of the container. Cover with foil and bake at 250°F (120°C) for 12 hours. For traditional method: Bury the sealed container in hot sand near a geothermal spring for 12-24 hours.
6. Cool and remove
   Once baked, remove the container from the heat source and allow to cool slightly. Open the container and turn out the bread onto a wire rack to cool completely.
7. Slice and serve
   Once cooled, slice the bread thinly. Thunder bread is traditionally served with butter and smoked salmon, or with a variety of toppings including cheese, pickled herring, or jam.