Combine sourdough discard, bread flour, 160 milliliters of cold water, and honey in a large mixing bowl; mix by hand for about 2 minutes until a rough, shaggy dough forms.

Cover the bowl with plastic wrap and let the dough rest at room temperature for 30 minutes for autolyse.

Add sea salt and remaining 20 milliliters of water to the dough; knead in a stand mixer with dough hook for 8 to 10 minutes or by hand for 12 to 15 minutes until smooth and elastic.

Transfer dough to a lightly oiled bowl, cover, and bulk ferment at room temperature for 3 to 4 hours until volume increases by about 50%.

Turn the dough onto a floured surface and divide into 8 equal pieces (~110 grams each); pre-shape each into a loose round.

Let the rounds rest under a towel or plastic wrap for 15 to 20 minutes on the bench to relax the gluten.

Punch a hole through the center of each round with your thumb and gently stretch into a ring with a 2 to 3 inch hole.

Place shaped bagels on parchment paper, cover loosely, and refrigerate for 8 to 16 hours overnight for cold retard.

Preheat a large pot of water to a rolling boil with 15 grams of baking soda; boil each bagel for 90 seconds per side, about 3 minutes total.

Preheat oven to 450°F (230°C); remove boiled bagels, place on a parchment-lined baking sheet, add toppings, and bake for 20 to 25 minutes until deep golden brown.