One-a-Day Baguette

In a large bowl sprinkle yeast and sugar over warm water and let stand until foamy, about 5 minutes. With a wooden spoon stir in 2 cups flour until combined. Stir in salt and 2 cups of remaining flour until mixture forms a stiff dough. On a lightly floured surface knead dough with lightly floured hands 8 minutes, or until smooth and elastic, kneading in enough of remaining 1/2 cup flour to keep dough from sticking. Transfer dough to a lightly oiled deep bowl, turning to coat with oil, and let rise, bowl covered with plastic wrap, until doubled in bulk, about 1 1/2 hours. Preheat oven to 400 ° F. Punch down dough and form into a long slender loaf about 21 inches long and 3 inches wide. Put loaf diagonally on a lightly greased large or 17- by 14-inch baking sheet and let rise, uncovered, about 30 minutes. (Baguette may be made up to this point 4 hours ahead and chilled.) Make 3 or 4 diagonal slashes on loaf with a sharp knife and lightly brush top with cool water. Bake loaf in middle of oven 30 minutes, or until golden, and transfer to a rack to cool.