In a large bowl, combine ½ cup warm water, yeast, and sugar. Let sit 10 minutes until foamy.
Add flour and salt. Pour in the remaining warm water and mix until a shaggy dough forms.
Knead on a lightly floured surface for 3–5 minutes until smooth and elastic.
Transfer to an oiled bowl, cover with plastic wrap, and let rise in a warm place for about 3 hours until doubled.
Turn the dough onto a floured surface, divide into equal portions, and pre-shape into balls. Rest 20 minutes.
Shape each into a long loaf and place seam-side down on a parchment-lined baking sheet or baguette pan.
Cover with plastic wrap and let rise 1½–2 hours until puffy.
Preheat oven to 425°F with a baking stone or inverted sheet pan on the middle rack and a pan on the lower rack.
Just before baking, pour 1 cup hot water into the lower pan to create steam.
Slash each loaf 4–5 times with a razor blade and bake 30–35 minutes, until deep golden brown.
Cool on a rack for 30 minutes before slicing.
Weighing ingredients is the most accurate way to bake, but cup measurements are included for convenience.