In a bowl or large liquid measuring cup, hydrate the psyllium husk with water, and then mix in the maple syrup, olive oil, and active sourdough starter. Let stand for about 10 minutes. It should form a thick, gel-like consistency.
150 g gluten-free sourdough starter, 20 g whole psyllium husk, 380 g filtered water, 20 g maple syrup or honey, 20 g olive oil
While that hydrates, mix together the tapioca flour, potato starch, sorghum flour, and brown rice flour (or my gluten-free bread flour blend) and salt in a large mixing bowl or the bowl of a stand mixer.
60 g potato starch, 50 g tapioca starch, 130 g superfine brown rice flour, 140 g sorghum flour, 12 g salt
Pour the liquid ingredients into the dry ingredients and use a dough whisk or the dough hook of your stand mixer to mix into a smooth dough, scraping down the sides as needed to make sure all of the dry ingredients are well incorporated.
Cover and let the dough bulk-ferment in a warm place for about three hours, or until noticeably puffy.
Punch down the dough to release the air bubbles, and then divide the dough into 8 equal pieces (about 122g each) and shape each piece into a bagel. I like to do this by rolling into a ball and then using my thumb to press a hole in the center, and then open the hole a bit more with my fingers. You can also roll the dough into a long piece and then seal the ends together.
Place the bagels on a lined baking sheet and cover with a clean tea towel; let rise for 1 hour.
While the bagels rise, preheat the oven to 425℉ and get a big pot of water boiling.
6 cups water
When the bagels have puffed up, add the baking soda to the boiling water and boil the bagels 1 or 2 at a time, depending on the size of your pot, for 30 seconds on each side. I use a spider to place the bagels in the water and remove them, as it allows excess water to drip off easily. Remove from the pot, letting the excess water drip off as much as possible, and place back down gently on the baking sheet.
1½ tablespoons baking soda
Repeat for all bagels and add any toppings, like everything bagel seasoning or other seeds of your choice. Immediately place into the preheated oven.
Bake for 30 minutes or until golden brown on top and crisp on the bottom.
To store, keep in an airtight bag or container for 2 to 3 days at room temperature. You can also slice them in half and store them in an airtight container in the freezer for up to 6 months.