In a small bowl, mix the ground flax seeds and the water. Set aside.
In a large bowl, add 100g of flour and mix in the steaming (hot) soy milk using a spatula. Allow the mixture to cool down for a few minutes. Add the yeast plus 1 tbsp of sugar and mix again using a whisk to avoid lumps. Let it proof, covered with plastic wrap, for 20 min.
Once the dough has grew in volume, add the rest of the sugar, the flax seeds, the orange zest, the vanilla extract, and the salt. Using your hand to mix, start incorporating the rest of the flour (350g). You may need to use less than 450g of flour depending on the brand you use.
Once the dough becomes more cohesive, gradually add the oil. Continue to kneed until all the oil is incorporated. In total, you’ll be kneading the dough for about 20 minutes. The dough should become very soft and still slightly sticky. Form a nice ball and let it proof in the bowl for about 1 hour, covered with plastic foil.
In the meanwhile, start preparing the filling. In another bowl, mix all the dry ingredients together and then incorporate the egg whites. Leave it aside.
Once the dough has doubled in size, remove it from the bowl and transfer it on your countertop. Slightly flatten it with your hands and cut it in 2 smaller balls. Take one of the balls aside. Add some oil on your countertop and on the dough, and continue to fatten and stretch it with your hands until it looks like a large oval about 1 cm thick. Spread half of the filling on the dough and roll it out on the longer side to form a long roll. Try to seal the roll as much as possible and repeat with the remaining ball.
Take the two rolls and braid them before transferring them into a loaf pan covered with parchment paper. Bake at 325°F for 60 minutes. Remove from the oven and coat with a bit of water mixed with sugar to give the loaf a nice shine.
Allow to cool down for at least 1h before cutting. I hope you’ll fall in love with this recipe as much as I did!