Mill the flour as fine as you can.
Make the yudane by mixing 25 grams of flour with 50 grams of boiling water.
If using active dry yeast, prove the yeast by adding it and the sugar to a small bowl with 50 grams of water, and set aside until yeast is added to the recipe.
Add water, egg, olive oil, sugar (if not used in the proving step), yudane and flour to your mixing bowl, and mix on low-medium speed for about 5 minutes.
Let the dough rest for 15-30 minutes.
Add the yeast, salt, and vitamin c to the dough, and mix for another five minutes or until windowpane is reached.
Let the dough rise until almost doubled.
Preheat oven to 375 F.
Shape the dough and let rise in your greased or lined bread pan until a finger pressed into the top doesn't spring back at you.
Bake the bread until the middle of the loaf is 190 F.
Remove from oven and pan, and cool on a wire rack before slicing.