To prepare dough, dissolve sugar and yeast in warm water in a large bowl; let stand 5 minutes. Lightly spoon flour into dry measuring cups; level with a knife. Add 1 cup flour and 1/4 teaspoon salt to yeast mixture; stir well. Add 1 cup flour, stirring well. Turn dough out onto a floured surface. Knead until smooth and elastic (about 10 minutes); add enough of remaining 1/4 cup flour, 1 tablespoon at a time, to prevent dough from sticking to hands (dough will feel tacky).
Place dough in a large bowl coated with cooking spray, turning to coat top. Cover and let rise in a warm place (85°), free from drafts, 45 minutes or until doubled in size. (Press two fingers into dough. If an indentation remains, dough has risen enough.)
Preheat oven to 450°.
Punch dough down; cover and let rest 5 minutes. Roll dough into a 14 x 12-inch rectangle on a lightly floured surface. Place dough on a baking sheet coated with cooking spray and sprinkled with cornmeal. Crimp edges of dough with fingers to form a rim. Bake at 450° for 5 minutes.
To prepare topping, combine squash, onion, and oil in a large bowl, tossing to coat. Place on a jelly-roll pan coated with cooking spray. Bake at 450° for 25 minutes or until tender, stirring once. Sprinkle with sage, 1/4 teaspoon salt, and pepper; toss to combine.
Set half of squash mixture aside. Combine remaining half of squash mixture and broth in a medium bowl; mash with a fork until smooth. Spread mashed squash mixture over pizza crust, leaving a 1/2-inch border. Top with remaining squash mixture, cheese, and bacon. Bake at 450° for 15 minutes or until lightly browned. Place the pizza on a cutting board; cut into 8 equal pieces.
Note: To freeze, let the dough rise once, punch down, and shape into a ball. Place in a heavy-duty zip-top plastic bag coated with cooking spray; squeeze out all air, and seal. Store in freezer for up to one month. To thaw, place dough in refrigerator for 12 hours or overnight. With scissors, cut away the plastic bag. Place dough on a floured surface, and shape according to recipe directions.