Use a kitchen scale to measure out your ingredients. That way you will get consistent results. Otherwise, use the "spoon & level" technique to measure your flour by spooning flour into your measuring cup and leveling it off with a knife. Don't scoop flour or pack it into the measuring cup or you'll end up using too much flour. See the Recipe Notes if you're using Active Dry yeast for an alternate way to start the dough.
Prepare the Dough: Combine the flour, sourdough starter discard, brown sugar, yeast, and salt together in the bowl of your stand mixer fitted with a dough hook attachment.
Pour in ¾ cup (170g) of warm water. Beat the mixer on low speed for 2 minutes, then knead for 4 to 5 minutes. Add in additional flour or water in one tablespoon increments to get the dough to the right texture.
Lightly grease a large bowl with oil. Place the dough in the bowl, turning it to coat all sides. Cover the bowl with a clean kitchen towel. Allow the dough to rise at room temperature for 60 to 90 minutes or until double in size (the inside the oven with just the light on works well).
Shape the Bagels: Punch down the dough to release any air bubbles. Divide the dough into 8 equal pieces, then shape each piece into a ball. Press your index finger through the center of each ball to make a hole about 1½ to 2 inches in diameter. Loosely cover the shaped bagels with a kitchen towel and rest for a few minutes as you prepare the water bath.
Preheat oven to 425°F.
Prepare the Water Bath: Fill a 4 to 8 qt stock pot with 2 quarts of water and whisk in the honey. Bring water to a boil, then reduce heat to medium-high. Drop the bagels in, 2 to 4 at a time, making sure they have enough room to float around. Cook the bagels for 1 minute on each side (2 minutes per side if you want a chewier bagel). Remove from pot and drain slightly. When cool enough to handle, gently reshape into bagel shape if needed.
Using a pastry brush, brush the egg wash on top and around the sides of each bagel. Dip in toppings, if desired. Place 4 bagels onto each lined baking pan.
Bake the Bagels: Bake for 20 to 25 minutes, rotating the pan halfway through. You want the bagels to be a dark golden brown. Remove from the oven and allow bagels to cool on the baking sheets for 20 minutes, then transfer to a wire rack to cool completely.
Cover leftover bagels tightly and store at room temperature for a few days or in the refrigerator for up to 1 week.
Using fed sourdough starter can give you a better rise (depending on how vigorous your starter is), but using unfed sourdough starter discard works just fine. If you do use fed starter (and it's active and bubbly), you can omit the yeast, but the rising times can be longer.If you use Active Dry yeast, then you might want to sprinkle yeast on to the warmed water with a teaspoon of sugar and allow it to sit for a few minutes before proceeding with the recipe. Letting it foam "proves" the yeast is active and ready to go to work.The amount of flour or water in your dough will depend on the humidity of your kitchen and the hydration of your starter. As you mix your dough, you might need to add more flour or water in one tablespoon increments to get the dough to the right consistency.The water temperature should be warm to the touch. Too warm, and you kill the yeast.Overnight Preparation: Prepare the dough through step 3, allowing the dough to rise overnight in the refrigerator. The slow rise gives the bagels wonderful flavor! In the morning, continue with step 4. I don't recommend shaping the bagels the night before as they may puff up too much overnight.Freezing: Freeze baked bagels for up to 3 months. Thaw overnight in the refrigerator or at room temperature, then warm to your liking. You can also freeze the bagel dough. After punching down the dough in step 5, wrap the dough tightly in plastic wrap, then a layer of aluminum foil. Freeze for up to 3 months. Thaw overnight in the refrigerator, then punch the dough down again to release any air bubbles. Continue with the rest of step 5.Bread Flour: Bagels require a high protein flour, so use bread flour if you can. You can make whole wheat bagels by replacing half of the bread flour with whole wheat flour.Bagel Varieties: The toppings are added after the egg wash in step 8. Dip the bagels into your desired toppings, then shake off excess.The ingredient amounts are for using 1 week's worth (8 oz, or 227g) of Sourdough Starter Discard. If you're going to use more or less starter, adjust the flour and water measurements accordingly (generally, starter is equal parts flour and water by weight). Either way, you might need to add more flour to get right dough consistency (flour is well hydrated).Don't skip the water bath and egg wash. Both provide an extra chewy and golden brown crust.