In a bowl, dissolve sugar in warm water. Sprinkle yeast over the top and let sit for 5–10 minutes until frothy.
In a large bowl, whisk flour and salt. Add the yeast mixture and softened butter. Mix until a shaggy dough forms.
Turn dough onto a floured surface and knead for 8–10 minutes (or use a stand mixer with a dough hook for 5 minutes) until smooth and elastic.
Place dough in a greased bowl, cover with a towel, and let rise in a warm place for 1 hour or until doubled in size.
Punch down dough, shape into a loaf, and place in a greased 9x5-inch loaf pan.
Cover and let rise for 30–45 minutes until the dough crests above the pan.
Preheat oven to 375°F (190°C). Bake for 25–30 minutes until golden brown and hollow-sounding when tapped.
Remove from pan and cool on a wire rack before slicing.
