Stir flour, fine sea salt, and yeast in a large bowl. Add water and olive oil. Mix with a spoon until you have a rough, sticky dough. Fold in rosemary and cranberries.

Cover the bowl with plastic wrap or a clean towel. Let it rest at room temperature for 12 to 18 hours until puffy with tiny bubbles.

Dust your counter with flour. Scrape the dough out and use floured hands to gently fold the edges toward the center a few times to make a loose ball.

Place the dough seam-side down on a floured piece of parchment. Cover and rest 30 to 45 minutes while the oven preheats.

Set a heavy lidded pot or Dutch oven in your oven and preheat to 450°F for at least 30 minutes.

Carefully lift the dough by the parchment and lower it into the hot pot. Sprinkle a little rosemary and coarse sea salt on top.

Bake for 30 minutes with the lid on, then 10 to 15 minutes uncovered until deeply golden.

Cool on a rack for at least 30 minutes before slicing. Resist cutting too soon so the crumb sets.