In a large bowl, stir together the all-purpose flour, sea salt, instant dry yeast, shredded sharp cheddar, shredded red cheddar, and diced jalapeños.
Pour in the lukewarm water and stir until a sticky dough forms.
Gently shape the dough into a rough ball as best you can right in the bowl. It will be sticky, do not worry about it.
Cover the bowl tightly with plastic wrap or a clean kitchen towel. Set it on the counter at room temperature and let it rise for 12–18 hours. The dough will double in size, stick to the sides of the bowl, and develop lots of air bubbles.
After the rise, turn the dough out onto a well-floured surface. Gently shape it into a round ball by folding it over itself a few times. Do not knead.
Place the dough seam-side down on a piece of parchment paper. Cover loosely with a towel while you preheat your oven.
Place your Dutch oven (with lid) into your oven and preheat to 450°F for at least 30 minutes.
Carefully remove the hot Dutch oven. Use the parchment paper to lift and transfer the dough into the pot. Score the top.
Cover and bake for 30 minutes. Remove the lid and bake uncovered for another 15–20 minutes, until the crust is deep golden brown.
Carefully remove the bread from the Dutch oven and let it cool on a wire rack for at least 1 hour before slicing.
