This is a bit of an unusual bread recipe. It's technically a "quick bread" as it's leavened with baking powder rather than yeast, but rather than spending a quick 30-60 minutes in the oven as most quick breads do, it gets steamed for several hours. Apparently the traditional way to bake this bread is by place in a pot and burying it near a geothermal spring to slowly steam its way to perfection. Given that geothermal springs aren't exactly commonplace here, I decided to steam mine in the InstantPot. This seems to have worked very well except for the part where I assumed that just having a lid on the casserole dish inside the pot would be enough and didn't bother trying to seal it. This resulted in a rather large amount of water finding its way into the baking dish so that the bread became quite wet around the edges. A quick blast in the dry heat of the oven seems to have dried it out without any ill effects though, so no major harm done!

There are a wide variety of recipes for Icelandic thunder bread floating around the internet. They all involve rye flour and baking powder. Interestingly, baking powder isn't always the only leavener; I came across one recipe that called for baking powder and yeast. Most just stick with a chemical leavener (like baking powder and/or baking soda) though. All the ones that I looked at also involved at least some amount of refined wheat flour. They also all call for a relatively high proportion of sweetener, but what that sweetener is varies from recipe to recipe. Some recipes call for granulated sugar, some use brown sugar; some add molasses, some don't. There's also usually some sort of dairy involved: usually milk, but sometimes buttermilk. There doesn't generally appear to be any fat added -- no oil or butter. So, quite a bit of variation overall, but the recipes still have enough in common that they're recognizable as thunder bread. They're a relatively sweet, steamed, chemically leavened, rye bread.

After browsing a few different recipes, I decided to go with the one I found on Spruce Eats as I liked the sound of all the brown sugar and molasses in their version. The smell and flavour is wonderful. It had a certain familiarity to it that I couldn't put my finger on at first. Then I realized... bran muffins! The flavour is very similar to bran muffins. The crust is chewier and the crumb is a little drier and less tender, but the flavour it definitely there. There is, of course, no wheat bran in this bread, but the whole rye flour means there's a fair bit of rye bran. That combined with the molasses is enough to tick the "bran muffin" box in my brain. This isn't necessarily a bad thing -- I quite like it honestly -- but it is a bit different than I was expecting. The molasses completely drown out any rye flavour. I think it'd be interesting to try one of the recipes that uses granulated sugar and no molasses next time to see how it compares. I'm hoping the rye will have more presence in those versions. As a side-note though, this does make a really nice low-fat alternative to bran muffins. Most bran muffins are just chock-full of oil! Often as much as half a cup of oil for a small batch of a dozen muffins. This bread hits a lot of the same notes for me without any of the added fat. (It's not fat-free; there's still some fat in the flours and the milk, but it's definitely much leaner than your typical bran muffin.) Neat!

Icelandic Thunder Bread

Slightly adapted from The Spruce Eats

Ingredients

• 330g whole rye flour
• 220g all-purpose flour
• 15g (~1 rounded Tbsp.) baking powder
• 1/4 tsp. coarse sea salt, ground
• 1/2 c. brown sugar
• 1 c. milk, scalded and cooled
• 1 Tbsp. molasses

Directions

1. Find a baking dish that will fit inside your InstantPot or slow cooker and grease it well.
2. Combine flours and sift in baking soda.
3. Add salt and brown sugar and mix well.
4. Dissolve molasses in cooled milk and add this mixture to the dry ingredients.
5. Stir to combine. Dough should be fairly wet, if it's not add a little water to loosen it up (1/4-1/2 c.)
6. Turn the dough out and knead it for a few minutes. It should become a little less sticky as you work it. If it reaches a point where it starts getting stickier or seems to be developing a slimy texture, stop working the dough immediately.
7. Place the dough into the prepared baking dish and cover. If you don't have a lid to fit the dish, cover it with foil. Make sure the edges are well-sealed in either case.
8. Put a trivet in the bottom of the InstantPot/slow cooker and add a few cups of hot water. (How much you need will depend on the size of your InstantPot/slow cooker and the size of your baking dish. The water should come about halfway up the side of the baking dish once it's lowered into the InstantPot/slow cooker.
9. Place the lid on the InstantPot/slow cooker and set to slow cook on "high" for four hours.
10. Remove the baking dish from the InstantPot/slow cooker at the end of the four hour cooking period and check on your bread. If any water has gotten into the baking dish, you may need to dry it out in the oven for a few minutes.
11. Once the bread is fully baked and dry, turn it out onto a wire rack to cool.
12. Once cool, slice thin and enjoy with smoked fish, paté, and/or cream cheese for a savoury option or nut butters, jams, and/or butter for a less traditional but equally delicious sweet option.