In a small bowl, dissolve the yeast in ½ cup of warm water. Cover with a plate to trap the heat and let it sit for about 5 minutes, until foamy and bubbly.
In the bowl of a stand mixer fitted with the dough hook, combine the sugar, salt, 2 cups of warm water, and melted butter. Add the proofed yeast mixture.
Gradually mix in the flour, one cup at a time, until a soft dough forms and pulls away from the sides of the bowl. Knead with the mixer for about 5 minutes. If the dough sticks to the sides, sprinkle in a little more flour as needed.
Transfer the dough to a lightly floured surface, knead a few times, then place it in an oiled bowl, turning to coat both sides. Cover with plastic wrap and let it rise until doubled in size, about 30 minutes to 1 hour.
Once risen, punch down the dough and divide it into two equal portions. Shape each portion into a loaf and place them in two greased sandwich baking pans. Cover with plastic wrap and let rise again until doubled, about 30 to 60 minutes.
Preheat the oven to 350°F. Remove the plastic wrap and bake for 20 to 30 minutes, until the crust is golden brown and sounds hollow when tapped.
Let the loaves cool in the pans for 10 minutes before transferring them to a wire rack to cool completely. Brush the tops with melted butter before serving.
Notes
Refrigerate: Store in a cool, dry place in an airtight container for up to 4 days.Freezer: Wrap tightly and freeze up to 3 months. Slice before freezing for convenienceThaw and Reheat: Allow the bread to defrost on your countertop. Toast slices or warm briefly in the oven at 300°F for 5–7 minutes.