Combine flour, 1 Tablespoon granulated sugar, instant yeast, and salt in the bowl of a stand mixer fitted with the dough hook attachment. Mix to combine.

On low speed, add the sourdough discard and warm water until combined. Increase speed to medium and knead for 4-5 minutes until a smooth ball forms.

Adjust flour or water as needed to achieve the right dough consistency.

Grease a large bowl, transfer the dough to the bowl, and cover with plastic wrap. Let the dough rise for 90 minutes or until doubled in size.

Turn the dough out onto a smooth surface and divide it into 8-10 equal pieces.

Roll each piece in your palm to form a smooth ball and use your thumb to press through the center of each ball to form a bagel.

Cover the bagels with a clean kitchen towel and let rest for 20 minutes.

Preheat oven to 425°F. Prepare 2 baking sheets lined with parchment paper.

Bring a pot with 2 quarts of water and 2 Tablespoons granulated sugar to boil.

Place bagels in boiling water for 15-30 seconds on each side. Remove from boiling water using a slotted spoon and transfer to the prepared baking sheets.

Whisk together the egg white and 1 Tablespoon water to create an egg wash. Lightly brush the bagels with the egg wash and sprinkle with toppings if using.

Bake for 18-22 minutes or until golden brown. Let cool fully before slicing and serving.