This recipe is from Dan Lepard. The bread doesn’t contain any egg, butter or milk products, but stays soft & moist for days because of the soya milk in it. It is because of the soya protein, you may see Dan’s reply here.
I used King Arthur All Purpose Flour and rye flour from a local shop to prepare the dough. The dough was quite sticky at the beginning, but after using Dan’s first fermentation method, gluten was formed like usual easily. The resulted crumb of the bread was soft but a bit chewy.
I could not taste the soy milk flavor in the bread, and the taste was similar to light wheat bread. There was also linseed in every bite. Crust was a bit thicker than usual. Overall, I like this healthy loaf and will make again. 
Recipe: In Dan Lepard’s Forum or the Guardian
I would definitely try soya milk in my next bread. Thanks for the tip.
hey~ long time no “leave msg”! hehe~
i can see that you’re turing into a bread expert! they all look soooooo nice!
I guess the magic of soya milk, that is , the soya oil.
I try many times. Fat can slower the degeneration of breads and also, the most important is that, don’t over baked the bread!!
My lightly baked bread with fat can retained one week without reheat, whereas the Frence breads, even gluten was well developed and with poolish and long fermintation, just 1/2 day live!
Hi! Silvia! Maybe it’s the blog design that makes my bread look more expert? ：ｐ
Hi! A Moon! I thought it was soy oil too, but I got a reply from Dan, it’s because of the soy protein. It’s a bit detailed but interesting. You may see the reply as in my edited post.
This is very hot info. I think I’ll share it on Twitter.