Stir yeast, sugar and 1/4 cup of warm water. Let it sit until it gets foamy, about 5 minutes. Add 1 Tbs. olive oil, the flour, 1 1/2 Tbs. rosemary, salt (fine) and 3/4 cup warm water, stir with a wooden spoon (or with dough hook on medium speed - with mixer - adding a little flour if the dough sticks to the bowl, about 8 minutes. Brush a large bowl with olive oil. Generously flour a work surface, turn the dough out and divide into 4 pieces. Working with 1 piece at a time, sprinkle flour on the dough, then fold the top and bottom portions into the middle. Fold in the sides to make a free-form square. Use a spatula to turn dough over, then tuck corners under to form a ball. Place seam side down on prepared baking sheet. Repeat with remaining dough, putting 2 balls on each sheet. Let stand uncovered, until more than doubled, about 2 hours. Preheat the oven to 400 degrees. Bake loaves 10 minutes; brush with remaining 1 Tbs. olive oil and sprinkle with the Kosher salt and remaining 1/2 Tbs. rosemary. Continue baking until golden brown, about 10 minutes. Cool. Serve with olive oil seasoned with pepper.