In a large mixing bowl, whisk together flour, instant yeast, and fine sea salt to distribute ingredients evenly.

Pour in lukewarm water and 2 tablespoons of olive oil. Stir with a spoon until a shaggy, wet dough forms with all flour incorporated.

Gently fold the dried cranberries and chopped fresh rosemary into the dough using a spatula, being careful not to crush the berries.

Cover the bowl with plastic wrap or a damp kitchen towel and let rest at room temperature for 12–18 hours until dough rises slightly and develops aroma.

Turn dough onto a lightly floured surface and gently shape into a round or oval loaf, folding edges toward center while preserving air bubbles.

Place seam-side up in a floured banneton basket or bowl lined with a floured kitchen towel. Cover loosely and let rise for 2–4 hours at room temperature or up to 8 hours refrigerated.

About 1 hour before baking, place a Dutch oven inside your oven and preheat to 475°F (245°C).

Turn risen dough onto parchment paper and score the top with 2–3 confident slashes using a sharp bread knife for a rustic appearance.

Carefully transfer dough on parchment into preheated Dutch oven. Cover with lid and bake for 30 minutes.

Remove lid and continue baking for 15–20 minutes until crust is deep golden brown.

Remove from oven and immediately brush hot crust with remaining 1 tablespoon olive oil. Sprinkle with fleur de sel while oil is still wet.

Transfer to a wire rack and cool completely for at least 30 minutes before slicing to allow crumb to set properly.