Chop the jalapeños in half (leave the seeds if you like spicy food) and then in slices. Saute them lightly in olive oil, to release flavor into the oil. Stop while they are still bright green.
Mix all of the ingredients together except the cheese. (You can add the cheese now if you really want, all will turn out fine.
Cover and let the dough ferment until puffy and bubbly, 5-10 hours depending on the room temperature. To strengthen the dough, you can do four rounds of stretching and folding at 30 minute intervals, after the mixed dough has rested 30 minutes. Or you can retard the dough in the refrigerator for 10-12 hours, which will also improve the gluten structure.
Cut 3/4 of an 8-ounce block of cheddar into small chunks, about the side of half of a domino. Slice the remaining 1/4 of the block into thin long slices and set aside for lining the proofing basket later if you want a cheesy crust.
Scrape your fermented dough out onto a floured counter and stretch it into a rectangular shape.
See the photo gallery for a visual explanation of the following instructions:Lay 1/3 of the cheese chunks into the middle third of your dough. Fold the left third over the middle. Lay another 1/3 of the cheese onto the dough that you just folded over. Cover it with the right third of the dough. Lay the remaining 1/3 of the cheese onto half of your now-narrow rectangle, then fold the other half over, onto the cheese.
Let the cheese-filled dough rest 15-20 minutes while you prepare your proofing basket. Options include sprinkling the basket lightly with bran flakes and lining it with your long, thin cheese slices.
Shape your dough gently into a boule or batard. I usually only flip it into the basket and then stitch the sides a bit.
Proof the dough 1-2 hours at room temperature or longer in the refrigerator. During the final 30 minutes of the dough's final proof, preheat your oven and baking vessel to 500F.
Flip your dough onto parchment or into your baking vessel. Make sure the cheese and bran-flake side is up. Note: If you have an unenameled clay baker, the cheese oil will stain or "season" the interior. Use parchment if you don't want this to happen. (I personally don't mind it.)
Score the dough, cover and bake as follows:500F for 20 minutes lid on450F for 10 minutes lid on450F for 5-15 minutes lid off
The internal temp of the bread should be 205F or higher. Be careful moving the bread around when it's still hot as oil from the cheese burns skin easier than dry bread crust.