To make the dough: Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. Combine all of the dough ingredients — by hand, mixer, or bread machine — mixing and kneading to form a smooth and shiny dough., Place the dough into a greased bowl, turn to coat, and cover., Place it in a warm spot to rise for 1 to 2 hours, until the dough has expanded by at least a third., Lightly grease (or line with parchment) a baking sheet., To assemble the loaf: Turn the dough out onto a lightly greased or floured surface, then pat it out into a 12" square., Sprinkle the dough with the onions and cheese., Fold it into thirds (like a letter) to enclose the onions and cheese., Form it into a 15" to 16" fat baguette — in other words, a bâtard. (Or divide and shape it into two smaller loaves)., Place the loaf/loaves on the baking sheet, and cover lightly with greased plastic wrap or a dough cover., Allow the bread to rise for 1 to 1 1/2 hours, or until doubled in size., To bake the bread: Toward the end of the rise, preheat the oven to 400°F., Just before placing the bread into the oven cut 4 to 5 diagonal slashes across the top, each about 1/4" deep., Spritz the bread with water, then place it into the oven., Bake it for 15 minutes, then reduce the oven heat to 350°F and bake for an additional 15 minutes (for 1 large loaf). For two smaller loaves, check after an additional 10 minutes. Bread is done when an instant-read thermometer inserted into the center registers 190°F., Store the bread, well-wrapped, at room temperature for up to 5 days or in the freezer for up to 3 months.