Combine the warm water, instant yeast, and brown sugar or maple syrup in the bowl of a mixer, then leave the mixture for 5 to 10 minutes. Continue when a layer of foam appears and the mixture smells lightly yeasty.

Add the vital wheat gluten, ground flaxseed, oat fiber flour, salt, nutritional yeast, and lactic acid liquid, then mix until a dough forms. The dough will look shaggy at first and should begin pulling away from the sides of the bowl.

Knead the dough at speed 3 to 4 for 8 minutes, then turn it out and shape it into a round ball by hand. It should feel smooth, firm, and elastic, with a little rebound when pressed.

Cover a very stiff dough and leave it to rest for 15 minutes, then use a few gentle kneading motions to tighten it into a ball. The rest allows the gluten to relax so the surface becomes easier to smooth.

Set the dough smooth-side up on a parchment-lined baking sheet, cover it with a damp lint-free kitchen towel, and proof it for 90 minutes in a warm place without drafts. Keep the towel damp so the dough does not form a dry skin as it expands.

After 60 to 75 minutes of proofing, preheat the oven to 400°F with one rack in the middle and another on the lowest level, then place a metal baking pan on the lower rack. Heat the oven fully before baking so the loaf gets strong oven spring.

At 80 minutes of proofing, bring water to a boil and reserve 75 ml for the lower baking pan. Having the water ready lets you create steam quickly when the loaf goes into the oven.

Once the loaf has fully risen and the oven is hot, uncover the dough and generously mist or brush it with water, then brush on oil after the water absorbs. The surface should look lightly hydrated and glossy before scoring.

Cut a C-shaped slash across the top with a sharp knife, or use another simple scoring pattern. The cut gives the dough a planned place to open instead of splitting unpredictably along the sides.

Set the loaf on the middle rack and carefully pour the 75 ml boiling water into the hot pan below it while wearing an oven mitt, then close the door promptly. The steam keeps the exterior supple during the early rise.

Bake for 30 minutes, raise the oven temperature to 425°F, and bake for 10 to 15 minutes more. The lifted edge of the score should become deeply browned, nearly charred around its thinnest edges.

Transfer the loaf to an elevated wire rack and let it cool completely before slicing. The interior finishes setting as steam escapes, leaving a cleaner, less gummy crumb.