Mix. In a large mixing bowl, combine the flour, water, salt, sugar, yeast, cheddar, and jalapeños. It's important to mix everything together at once so that the cheese and peppers will disperse easily. Use a rubber spatula to mix well, incorporating any dry areas of flour. The dough should form a shaggy ball. If there are any dry bits that are not being incorporated, add a few more teaspoons of water and mix again.
Cover and rise. Tightly cover the bowl of dough with plastic wrap. Place the covered bowl on the counter and allow it to rise for ten hours. Ideally, it will have doubled in size. If the dough has not changed much in size, give it more time to rise on the counter. You can always place the dough in the fridge to slow the process down and start again later.
Shape. Prepare a baking sheet by lining it with parchment or spraying it generously with nonstick cooking spray. This bread can really stick to the pan as the cheese melts, so if you have parchment paper, be sure to use it. Gently pick the dough out of the bowl and shape it into a smooth ball. Pull from the bottom of the dough to smooth out the top rather than smashing the dough down. Deflate any large air bubbles that have formed. Place the dough onto the prepared baking sheet. If you'd like a fancier-looking loaf, sprinkle with flour and place slices of jalapeño on top. Using a very sharp knife or lame, make a slash in the center of the loaf, cutting around a ¼ inch deep.
Second rise. Prepare a warm place for the second rise, either by briefly turning on your oven or placing a bowl of hot water inside it. Cover the ball of dough with greased plastic wrap, making sure that the loaf is completely covered. Let it rise in a warm place for about 45 minutes, until puffy but not quite doubled in size. Towards the end of the rising time, preheat the oven to 425℉ with the rack in the center. Be sure to remove the dough first.
Bake. Bake the loaf for 35-40 minutes at 425℉. The finished loaf will be deep golden brown and have an internal temperature of 200 degrees. Some cheese may have leaked from the loaf, but don't worry, most will still be inside. Carefully remove the bread from the baking sheet and place it on a cooling rack. Let it cool for at least thirty minutes before serving. If you cut into the loaf too soon, the cheese can leak out.
Notes
If you don't have jalapeño peppers (or aren't a fan!), you can substitute diced green bell peppers or just leave them out