01 - Combine bread flour and water in a large mixing bowl, mixing until just incorporated. Cover the bowl and let the mixture rest for 30 minutes to allow proper hydration (autolyse stage).
02 - Add the active sourdough starter and sea salt to the autolysed dough. Mix thoroughly until the starter is evenly distributed and salt is fully dissolved throughout the dough.
03 - Perform stretch and folds every 15 minutes for one hour (total of 4 sets). Grab a portion of dough, stretch it upward, and fold it over the center. Rotate the bowl and repeat until all sides have been folded.
04 - After completing the final stretch and fold, gently incorporate the cubed cheddar cheese and chopped jalapeños. Use light kneading motions to distribute them evenly without tearing the gluten network.
05 - Cover the dough and allow it to ferment at room temperature for 4 to 6 hours. The dough should approximately double in size and show visible fermentation bubbles on the surface.
06 - Turn the fermented dough onto a lightly floured work surface. Shape it into a tight round loaf by folding the edges toward the center and creating surface tension. Transfer to a floured proofing basket or lined bowl, seam-side up.
07 - Cover the shaped loaf and proof for 2 to 4 hours at room temperature, or refrigerate overnight (8 to 12 hours) for enhanced sour flavor development. The dough should puff noticeably and show slight resistance when pressed gently.
08 - Position oven rack to center position and place a Dutch oven inside. Preheat to 450°F for at least 30 minutes to ensure both oven and cooking vessel are thoroughly hot.
09 - Lift the dough onto a piece of parchment paper. Use a sharp knife or bread lame to score the top of the loaf with a single deep cut or decorative pattern. Transfer the parchment and dough into the preheated Dutch oven.
10 - Place the lid on the Dutch oven and bake for 20 minutes. The covered environment creates steam, allowing the bread to expand fully before the crust sets.
11 - Remove the Dutch oven lid and continue baking for 20 to 25 minutes. The crust should develop a deep golden-brown color and feel hard and crusty when tapped.
12 - Transfer the baked loaf to a wire cooling rack. Allow it to cool for at least 1 hour before slicing. This critical step completes the cooking process and ensures proper texture throughout.