Preheat the oven to 475 degrees. Wrap the head of garlic in foil and roast in the oven until very soft, about 45 minutes to an hour. Let cool, then squeeze garlic cloves out of the papery skins into a bowl and mash (discarding skins).

In a large bowl, whisk together half the flour and sea salt. Make a well in the center and place yeast in it. Pour in all but 1/2 a cup of the warm water and stir flour into the yeast and water just enough to make a sponge (moist mixture with still some flour around it. Cover bowl and set aside in a warm place until the sponge with the yeast is bubbly, 20 minutes. Stir in roasted garlic and 1/4 cup more water and the remaining flour (plus more water if needed to make a soft but not too sticky dough. Turn out onto a lightly floured surface and knead for about 8-10 minutes until elastic and smooth (adding a little flour if neccesary). Place in an oiled bowl, cover and let rise, about 45 minutes until doubled in bulk. Punch down and let rise again. Punch down and divide into 2 pieces. Roll each out into a 14 inch long rectangle and roll up (pinching seams and tucking ends) to shape into a loaf. Place on a parchment lined baking sheet, and slash each lightly diagonally down the center. Cover with plastic wrap and let rise until almost doubled in bulk. Meanwhile, preheat the oven to 475 degrees with the rack in the top/middle position. When dough has risen, lightly brush with olive oil and sprinkle with a little fleur de sel. Bake for 15-20 minutes until 190-200 degrees in the center or sounds hollow when tapped on the bottom. Cool on a rack and serve slightly warm if you want a real treat!