Prep the pan: Lightly oil a 9x5-inch loaf pan and line it with a parchment sling for easy removal. Set aside.

Bloom the psyllium: In a medium bowl, whisk the warm water, olive oil, and vinegar. Sprinkle in the psyllium husk, whisk again, and let it sit for 2–3 minutes until it thickens into a gel. This step is key for structure.

Mix the dry base: In a large bowl, combine the gluten-free flour blend, almond or oat flour, ground flaxseed, sugar, instant yeast, and salt. Whisk well so the yeast and salt are evenly distributed.

Add the seeds: Stir in the chia, sunflower, pumpkin, sesame, and any optional poppy seeds. Reserve a small handful for topping if you like.

Bring it together: Pour the psyllium gel into the dry ingredients. Use a sturdy spatula to mix until a thick, sticky dough forms. It should hold together but won’t feel like traditional wheat dough.

Pan and smooth: Scrape the dough into the prepared loaf pan. Wet a spatula or your fingers to smooth the top. Sprinkle with the reserved seeds and a pinch of flaky salt if using.

Proof: Cover the pan loosely with a clean towel. Let the dough rise in a warm spot for 35–55 minutes, or until it’s puffed by about 30–40%. Do not overproof—gluten-free dough won’t double like wheat dough.

Preheat the oven: While the loaf proofs, preheat to 375°F (190°C). Place a rack in the lower-middle position.

Bake: Bake for 45–55 minutes, until the top is deeply golden and the internal temperature reaches about 205–210°F (96–99°C). If the top browns too quickly, tent with foil for the last 10–15 minutes.

Cool properly: Let the bread cool in the pan for 10 minutes, then transfer to a wire rack. Wait at least 1 hour before slicing so the crumb sets and stays moist.