Feed your starter: 4-12 hours before making your dough, feed your sourdough starter.
Make the dough: In a stand mixer, combine the sourdough starter, water, honey, salt, and 2 cups of the flour. Mix on low speed for about 2 minutes. The dough will be very stiff at this point.
Add remaining flour: Slowly add the remaining flour, 1/2 cup at a time, while continuing to mix. Knead the dough with a dough hook until smooth and pliable. The dough should hold is shape well and not be sticky or wet. The amount of flour will depend some on how humid your kitchen is so keep adding until you get a nice smooth dough.
First rise: Transfer the dough to a non-metal bowl. Cover the dough with a wet tea towel, plastic wrap, or beeswax wrap. Let it ferment for 8 to 16 hours.
Shape the bagels: After fermentation, divide the dough into 8 equal pieces. Roll each piece into a ball, slightly flatten it, use your finger to poke a hole in the middle. Stretch the hole slightly to widen it. Repeat with remaining dough. Cover the shaped bagels with a tea towel and let the dough rise in a warm spot for 1 to 4 hours, or until puffy.
Preheat the oven: Preheat your oven to 425°F (218°C).
Boil the bagels: Bring 2 quarts of water to a boil in a large pot. Add the baking soda. Gently place the bagels into the boiling water (2-4 at a time) and boil for 1 minute per side. Use a slotted spoon or spider strainer to flip and remove the bagels from the water.
Add toppings (optional): Shake off excess water and sprinkle the bagels into your desired toppings.
Bake: Place the bagels on a parchment-lined baking sheet and bake for 20-25 minutes, or until golden brown on top.
Notes
If the dough is a little softer after the first rise, you can use some flour on your work surface and hands.
Add your toppings while the bagels are still wet from boiling. This will help the toppings stick.
This dough can be stiff, so be patient. A stand mixer makes this process much easier.
Don't skip boiling the bagels before baking, as this gives them that classic chewy crust!