1. In large bowl, sprinkle yeast over warm water. Let stand until foamy, about 5 minutes. Stir to dissolve yeast.
2. To yeast mixture, add 2-1/2 cups of the flour, the olive oil, sage and salt; stir briskly with wooden spoon until smooth. Stir in the remaining 2-1/4 cups flour just until dough begins to pull away from the side of the bowl; dough will be fairly wet and sticky.
3. Cover the bowl with plastic wrap and a clean kitchen towel. Let the dough rise in a warm place, away from drafts, until doubled in volume, about 30 minutes.Onion and Pancetta Topping:
4. Meanwhile, in large skillet, heat 1 tablespoon oil over medium heat. Add onions, red pepper and pancetta; cook, stirring occasionally, until vegetables are tender, 12 to 13 minutes. Set aside.
5. Heat oven to 500 degrees F. Coat 15 x10 x 1-inch jelly-roll pan with nonstick cooking spray. Scrape dough onto prepared pan, scraping it from sides of bowl with rubber spatula. Gently spread to fill pan.
6. Gently brush dough with the remaining 1 tablespoon olive oil. Dip fingers into cold water, then into dough to make indentations. Gently spread top with onion mixture. Sprinkle with coarse salt.
7. Place dough in 500 degree F oven; reduce oven temperature to 400 degrees F. Bake 30 to 35 minutes or until crust is browned and sounds hollow when tapped with finger. Remove from pan to wire rack; let cool slightly. Cut into twenty-five 3 x 2-inch pieces. Serve warm or at room temperature. Makes 25 pieces.