In a large bowl stir flour salt and yeast.
Add warm water and mix with a spoon until no dry spots remain. The dough will feel sticky.
Fold in the mashed roasted garlic and the rosemary.
Cover the bowl and let the dough rise at room heat until puffy and doubled, about 60 to 90 minutes.
Set a Dutch oven with lid in the oven and heat to 230 C or 450 F.
Lay a sheet of parchment on the counter and dust with flour. Turn the dough out and shape into a round ball.
Lift the dough with the parchment and set it in the hot Dutch oven. Cover and bake 30 minutes.
Uncover and bake 12 to 18 minutes more until deep golden and crisp.
Cool on a rack at least 30 minutes before slicing.