Dissolve yeast in warm water. Stir in sugar, then 1/2 cup of flour until smooth. Let stand until mixture begins to bubble (5 or 10 mins).
Combine remaining flour and salt. Stir into yeast mixture along with rosemary. (Basil, oregano, thyme, etc work well too) Turn onto lightly floured surface and knead until smooth and elastic, about 10 mins. Cover and let rise until doubled in size, about 1 hour.
Punch down dough. Roll into 9-inch circle. Place on baking sheet sprinkled with cornmeal. Brush bread with oil mixed with garlic. Sprinkle cracked pepper and crushed rock salt over top. (May also use Parmesan cheese, if desired, or tomato slices or whatever else sounds good.) Using two fingers, punch holes evenly all over top of bread. Let stand about 15 mins. Bake at 425 for 15-20 mins. until golden brown.