Preheat oven to 450°. Roll the dough into an 11 x 15 inch rectangle and place it on a lightly oiled baking sheet. Prick the dough all over with a fork. In a small bowl, combine the water, 1 tablespoon of salt and 2 tablespoons of the oil; brush over the dough. Let the dough rise for about 30 minutes. 2. In a large, heavy skillet, combine the remaining 3 tablespoons of oil with onions, garlic, bouquet garni, and 1 teaspoon salt. Sweat, covered, over low heat until the onions are soft and cooked through, about 30 minutes; they should not brown. Discard the bouquet garni and spread the onion mixture evenly over the bread dough.