01 - Dissolve sugar in warm water in a large bowl. Sprinkle yeast over the surface and let stand 5–10 minutes until foamy.
02 - Stir salt and oil into the yeast mixture. Gradually add flour, 1 cup at a time, mixing until a soft dough forms that pulls away from bowl sides.
03 - Knead on a lightly floured surface for 6–8 minutes until smooth and elastic.
04 - Place dough in a greased bowl, cover, and let rise in a warm place until doubled, about 1 hour.
05 - Punch down dough and divide in half. Shape each half into a loaf and place in two greased 9x5-inch loaf pans.
06 - Cover pans and let rise until dough extends 1 inch above the rim, about 30–45 minutes.
07 - Preheat oven to 350°F.
08 - Bake for 25–30 minutes until golden brown and loaves sound hollow when tapped.
09 - Brush tops with melted butter if desired. Remove from pans and cool on a wire rack before slicing.