Mix the psyllium husk powder with the warm water in a small bowl.

Stir quickly and let it sit for 2 minutes until it gels into a thick slurry.

Add the starter, olive oil, honey or sugar, and sea salt to a large bowl.

Stir until the starter dissolves into the liquids.

Add the brown rice flour, tapioca starch, potato starch, and baking powder to the bowl.

Pour in the psyllium gel.

Mix vigorously for 2 minutes until the batter is thick and cohesive.

Line a 9x5 loaf pan with parchment paper.

Scrape the batter into the pan.

Smooth the top with wet fingers.

Cover the pan loosely.

Let it rise at warm room temperature for 60–90 minutes until it crowns just above the rim.

Preheat the oven to 400°F.

Bake for 50–55 minutes.

Remove the loaf from the pan.

Place the loaf directly on the oven rack and bake for 10 more minutes.

Cool completely for at least 2 hours before slicing.