Preheat oven to 450°F. Have ready a long sheet of aluminum foil big enough to envelope 5 heads of garlic. Leaving the garlic heads intact, peel away the loose outer skin and cut off about 1/4" of the top of the heads, exposing the tops of all the garlic cloves.

Place the heads on the aluminum foil and drizzle with olive oil. Sprinkle thyme, 1/2 teaspoon salt and black pepper over the top of the garlic heads. Make a packet from the aluminum foil and bake in preheated oven for 30-40 minutes until soft. Remove from oven to cool. When cool enough to handle, squeeze the garlic cloves from the heads into a small bowl and set aside.

Place yeast in a large bowl and add water. Stir to combine, then add flour, roasted thyme garlic cloves, salt, rosemary and parmesan cheese. Stir together until everything is moistened and comes together using a wooden spoon or your hands, as necessary.

Cover with plastic wrap and set at warm room temperature to rise for 3 hours. After 3 hours, transfer dough to the refrigerator overnight.

Remove the dough from the refrigerator and set on the counter. Place a metal baking pan on the bottom baking rack of the oven and fill with water. Turn oven on and set it to 450°F. Butter a baking sheet and sprinkle with cornmeal. Set aside.

Remove dough from the bowl and transfer to a floured work surface. Sprinkle the top with flour and using floured hands, split the dough into two halves and shape into rounds.

Sprinkle loaves again with flour and then allow them to rest 45 minutes at warm room temperature.

Using a very sharp knife, cut an "X" in the top of each loaf then bake in preheated oven for 30 minutes.

Remove from oven and cool at least 15 minutes before slicing. Serve warm or at room temperature.