In a large bowl stir together 2 3/4 cups of the flour, 1 1/2 tsp. of the salt, and the yeast. Stir in the warm water (dough will be sticky and soft). Cover and let rest 2 hours.
Lightly grease a 12-inch cast-iron or other heavy oven-going skillet. Using a fork, stir remaining 1 cup flour into dough; spread slightly in prepared skillet. Cover dough with lightly greased plastic wrap and let rise at room temperature until puffy (1 1/2 to 2 hours).
Preheat oven to 400 degrees F. Sprinkle dough with olives, rosemary, and garlic; drizzle with 1 Tbsp. of the oil and sprinkle with remaining 1/4 tsp. salt. Cook over medium-high heat 3 minutes. Transfer to oven and bake 30 minutes or until golden. Cool in skillet on a wire rack 15 minutes. Drizzle with remaining 1 Tbsp. oil. Serve warm.