Combine 1 cup of the flour, yeast and salt in a large bowl.
Heat 2 tablespoons of the oil, rosemary and 1 cup water in a saucepan until very warm (125°F to 130°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.
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.
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.
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.
Heat oven to 400°F. Sprinkle cheese evenly over top. Bake at 400°F for 20 to 25 minutes, until lightly browned and cheese is melted. Cut into 12 pieces. Serve warm.