Make the Poolish: 3-4 hours before bed (or up to 24 hours), mix 1 cup flour, 1 cup water, and 1/4 tsp yeast in a large bowl until smooth. Cover and let sit until bubbly and frothy.

Mix Final Dough: To the active poolish, add 3 cups flour, 1 cup water, salt, and optional yeast. Mix with a dough whisk until no dry flour remains. Dough will be very wet and sticky. Cover bowl tightly.

First Rise (Overnight): Let the covered dough rest at room temperature (70-75°F) for 12-14 hours, until bubbly and more than doubled.

Shape: Generously flour a work surface and your hands. Gently scrape the dough out. Perform a series of stretches and folds, then shape into a round or oval. Place seam-side up in a heavily floured banneton or towel-lined bowl.

Final Proof: Cover the shaped loaf and let rise for 1-1.5 hours at room temp. 45 mins before baking, preheat oven to 450°F with a baking stone and a rimmed baking sheet inside.

Score & Create Steam: Turn proofed loaf onto parchment paper. Slash the top deeply with a razor. Slide loaf on parchment onto the hot stone. Immediately throw ice cubes into the preheated rimmed sheet to create steam. Close door quickly.

Bake: Bake with steam for 20 mins. Remove steam pan, reduce heat to 400°F, and bake 25-30 mins more until deep golden brown and hollow-sounding when tapped.

Cool Completely: Transfer bread to a wire rack immediately. Let cool for at least 2 hours before slicing to prevent a gummy crumb.