1. Combine 1 cup of the flour, yeast and salt in a large bowl.
2. Heat 2 tablespoons of the oil, rosemary and 1 cup water in a saucepan until very warm (125 degrees F to 130 degrees F). Gradually beat water mixture into flour mixture with a wooden spoon. Beat in 1-1/2 cups of the remaining flour, 1/2 cup at a time, to make soft dough.
3. Knead dough on floured surface until smooth and elastic, 10 minutes, working in remaining 1/2 cup flour as needed to prevent sticking. Shape into ball. Cover; let rest 10 minutes.
4. Saute bacon in skillet over medium heat for 4 to 5 minutes until crisp. Add spinach; cook an additional 1 to 2 minutes. Set aside.
5. Roll out dough on a floured surface to 15 x 11-inch rectangle. Fit in greased 15 x 11 x 1-inch jelly-roll pan. Make indentations all over surface of dough, pressing almost to bottom of pan. Drizzle dough with remaining tablespoon oil. Scatter bacon-spinach mixture and sea salt over top. Cover with plastic wrap. Let rise in warm place until almost doubled, 30 minutes.
6. Heat oven to 400 degrees F. Sprinkle cheese evenly over top. Bake at 400 degrees F for 20 to 25 minutes, until lightly browned and cheese is melted. Cut into 12 pieces. Serve warm.