Warm 1 cup of water to about 80°F (27°C). Stir in 1 cup sourdough discard and 1 teaspoon active dry yeast until dissolved.

Add 3 cups bread flour and 1.5 teaspoons salt. Mix until just combined into a shaggy dough.

Rest for 20 minutes (autolyse). This improves hydration and gluten development.

Perform a gentle stretch-and-fold: wet your hand, lift one side of the dough, fold it over. Repeat on each side. Repeat this sequence twice at 15-minute intervals.

Lightly flour your work surface and shape the dough into a tight batard or two smaller loaves.

Place the shaped loaf on a parchment-lined baking sheet or in a floured couche. Cover with a towel and proof at room temperature for 30–45 minutes, until puffy but not doubled.

Preheat the oven to 450°F (230°C). Place a shallow pan on the bottom rack to create steam.

Just before baking, slash the loaf with a sharp blade — 3–4 shallow diagonal cuts.

Pour a cup of hot water into the shallow pan to create steam, quickly close the oven, and bake for 20–28 minutes until golden and hollow-sounding when tapped.

Aim for an internal temperature of about 200–205°F (93–96°C).

Cool on a rack for at least 20 minutes before slicing.