1. Combine Wet Ingredients: In a large mixing bowl, whisk together the sourdough discard, warm water, sugar, and salt until well combined. The mixture might look a little lumpy, which is perfectly fine.

2. Add Flour and Form Dough: Gradually add the all-purpose flour to the wet mixture, stirring with a wooden spoon or spatula until a shaggy dough forms. Once it’s too stiff to stir, turn it out onto a lightly floured surface and knead for about 5-7 minutes until the dough is smooth and elastic. It should spring back slowly when poked.

3. First Rise (Overnight): Place the kneaded dough into a lightly oiled bowl, turning it once to coat. Cover the bowl tightly with plastic wrap or a damp kitchen towel and refrigerate for 8-12 hours, or overnight. This slow, cold fermentation develops flavor and makes the dough easier to handle.

4. Shape the Bagels: The next morning, gently punch down the dough and divide it into 8-10 equal pieces. Roll each piece into a smooth ball. To form the bagel shape, you can either poke a hole through the center of each ball with your thumb and gently stretch it to about 1-inch in diameter, or roll each piece into a 6-inch rope and connect the ends to form a circle. Place the shaped bagels on a parchment-lined baking sheet.

5. Boil the Bagels: Preheat your oven to 425 F (220 C). Bring a large pot of water to a rolling boil and add the baking soda. Carefully drop 2-3 bagels into the boiling water at a time (don’t overcrowd the pot). Boil for 60 seconds per side. Using a slotted spoon, remove the bagels and place them back on the parchment-lined baking sheet.

6. Add Toppings and Bake: If desired, sprinkle your chosen toppings (sesame seeds, poppy seeds, etc.) onto the boiled bagels immediately after removing them from the water, as they will stick better. Bake for 20-25 minutes, or until the bagels are golden brown and sound hollow when tapped on the bottom.

7. Cool and Serve: Transfer the baked bagels to a wire rack to cool completely before slicing and serving. This allows the internal structure to set, resulting in a better texture.