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