1. 1. Mixing the Dough: In a large mixing bowl, combine the active sourdough starter, warm water, and 1 tablespoon of granulated sugar. Stir until the starter is mostly dissolved. Add the bread flour and salt, mixing with a wooden spoon or your hands until a shaggy dough forms and no dry flour remains. Cover the bowl with a damp cloth or plastic wrap and let it rest for 30 minutes. This is called autolyse and helps the flour absorb the water.

2. 2. Developing the Dough Strength: After the rest, perform a series of “stretch and folds” every 30 minutes for 2 hours. To do this, lightly wet your hands, grab a portion of the dough from one side, stretch it up, and fold it over to the center. Rotate the bowl a quarter turn and repeat this process 3-4 times. This builds gluten development without extensive kneading. After the 2 hours, cover the bowl and place it in the refrigerator for 8-12 hours (or overnight) for a slow, cold proof. This develops deep flavor.

3. 3. Shaping the Bagels: The next day, remove the dough from the refrigerator. Divide the dough into 8 equal pieces (about 100-110 grams each). To shape a bagel, roll each piece into a tight ball. Then, poke a hole in the center with your thumb and gently stretch the hole to about 1-1.5 inches in diameter, trying to keep the bagel uniform in thickness. Place the shaped bagels on a parchment-lined baking sheet.

4. 4. The Float Test and Preheat: Fill a large pot with water and bring it to a rolling boil. Add 2 tablespoons of sugar or malt syrup to the boiling water. While the water heats, preheat your oven to 425 F (220 C) and place an oven rack in the middle position. To check if your bagels are ready for boiling, drop one into a bowl of water; if it floats within 10-15 seconds, they are ready. If not, let them rest at room temperature for another 15-30 minutes and re-test.

5. 5. Boiling and Topping: Carefully lower 2-3 bagels into the boiling water, ensuring they don’t overcrowd the pot. Boil for 30 seconds to 1 minute per side. Use a slotted spoon to remove them, letting excess water drip off, and place them back on the parchment-lined baking sheet. Brush the tops of the boiled bagels with the lightly beaten egg white and generously sprinkle with everything bagel seasoning.

6. 6. Baking to Golden Perfection: Transfer the baking sheet to the preheated oven. Bake for 20-25 minutes, or until the bagels are golden brown and sound hollow when tapped on the bottom. If you notice them browning too quickly on one side, rotate the baking sheet halfway through baking. Once baked, transfer the bagels to a wire rack to cool completely before slicing and serving.