01 - Combine bread flour and water in a large bowl, mixing until just incorporated. Cover the bowl and let rest for 30 minutes to allow flour hydration.
02 - Add sourdough starter and sea salt to the dough. Mix thoroughly until fully integrated and dough begins to develop structure.
03 - Perform stretch and fold technique four times at 15-minute intervals over one hour. Grab one edge of dough, stretch upward, and fold over center. Rotate bowl and repeat.
04 - After final stretch and fold, gently work cubed cheddar and chopped jalapeños into dough until evenly distributed.
05 - Cover dough and allow to rise at room temperature for 4 to 6 hours, or until doubled in volume. Dough should show bubbles and increased volume.
06 - Turn dough onto lightly floured surface. Shape into tight round by folding edges toward center, creating surface tension. Place in floured proofing basket seam-side up.
07 - Cover and proof for 2 to 4 hours at room temperature, or refrigerate overnight for enhanced flavor development.
08 - Position Dutch oven in oven and preheat to 450°F for at least 30 minutes to ensure thorough heat penetration.
09 - Lift dough onto parchment paper using proofing basket. Score top of loaf with sharp knife or lame, then transfer into preheated Dutch oven.
10 - Bake with lid on for 20 minutes to create steam and oven spring.
11 - Remove lid and continue baking 20 to 25 minutes until deep golden brown and crust sounds hollow when tapped.
12 - Transfer loaf to wire rack and cool for minimum 1 hour before slicing to allow internal crumb to set.