Preheat your oven to 400ºF (204ºC). Cut the top off a head of garlic, drizzle with olive oil, wrap in foil, and roast for 40 minutes.

In a mixing bowl, combine warm water and active dry yeast. Let sit for 10-15 minutes until frothy. In another bowl, whisk all-purpose flour, coarse sea salt, and chopped rosemary.

Add smashed roasted garlic and olive oil to the yeast mixture, mix until just combined. The dough should be sticky.

Cover the bowl with a kitchen towel and let it rise for 8-10 hours until it doubles in size.

Turn the dough out onto a floured surface and shape it into a rough ball. Place it seam side up in a floured bowl, cover, and refrigerate for 12-48 hours.

Preheat the oven to 450ºF (232ºC) with a Dutch oven inside. Transfer the dough onto parchment, score the top, and bake covered for 30 minutes, then uncover and bake for 15-20 minutes.

Remove the bread from the Dutch oven and place on a cooling rack for up to an hour before slicing.