In a mixing bowl, combine the all-purpose flour, sourdough discard, salt, sugar, and instant yeast. Mix well to blend the dry ingredients.
Gradually add the warm water to the mixture, stirring with a wooden spoon or spatula until a rough dough begins to form.
Knead the dough on a lightly floured surface for about 5-7 minutes until it becomes smooth and elastic.
Shape the dough into a ball, place it in a greased bowl, and cover it with a clean cloth. Let it rest for 30 minutes.
Preheat your oven to 450°F (230°C) and line a baking sheet with parchment paper.
After resting, punch down the dough and divide it into 8 equal pieces. Shape each piece into a ball and poke a hole in the center with your finger to create the bagel shape. Gently stretch the hole to ensure it remains open after baking.
In a large pot, bring water to a boil and add the baking soda. Carefully drop in the bagels (you may need to do this in batches) and boil for about 30 seconds on each side. Remove them with a slotted spoon and place them on the prepared baking sheet.
If desired, sprinkle your favorite toppings onto the bagels while they are still wet from boiling.
Bake the bagels in the preheated oven for 20 minutes or until golden brown.
Allow the bagels to cool on a wire rack before serving.