Dissolve sugar into the hot water in a 2-cup measure; add yeast and stir gently. Let dissolve until top is foamy, about 5 minutes.

Whisk flour and salt together in a large bowl. Make a well in the center and pour in the yeast mixture. Stir gently, starting from the middle, until mixture is sticky. Knead by hand, adding more flour if needed, until dough is elastic and no longer sticky, about 10 minutes.

Oil a large, clean bowl and place dough inside, turning to coat. Cover with a towel and let rise in a warm place until doubled in volume, about 1 hour.

Preheat the oven to 425 degrees F (220 degrees C). Fill a roasting pan with water and set on the lower rack of the oven. Line a baking sheet with a silicone mat.

Punch down dough and turn onto a lightly floured surface. Shape dough into 1 large loaf or 6 sandwich loaves, tapering the ends. Place loaves on the prepared baking sheet. Cut 3 or 4 diagonal slashes, about 1/4 to 1/2-inch, across the tops. Cover with a dry towel and let rise until doubled in volume, about 40 minutes.

Uncover and bake in the center of the preheated oven until top is light golden brown, 15 to 20 minutes depending on the size of the loaves.