In the bowl of a stand mixer, dissolve the yeast and sugar in the warm water.
Let stand for 5 minutes to get foamy.
Mix in the butter, salt, and 3 cups of flour with a dough hook.
Once well combined, add the last cup of flour, ¼ cup at a time, until the dough forms a ball, pulls away from the sides of the bowl, and is only slightly sticky to the touch. YOU MAY NOT NEED THE ENTIRE LAST CUP OF FLOUR.
Knead for 3 minutes at medium speed or 5 minutes by hand.
Cover the bowl with a dishcloth and allow the dough to rise until doubled. (around 30-ish minutes)
Dump the risen dough out onto a lightly floured surface and shape it into a loaf.
Place in a loaf pan that's been sprayed with non-stick cooking spray.
Cover and let rise until doubled. (around 30-ish minutes)
Adjust your oven racks so that the bread will bake right in the center of the oven.
Preheat your oven to 350 degrees.
Bake the bread at 350 degrees for 20 minutes, tent with some tin foil, and continue to bake for another 25 minutes.
Your bread loaf should sound hollow when thumped.
Run a small cube of butter over the top of the hot bread loaf if desired, and let cool for 10 minutes in the bread pan before turning it out onto a wire rack to cool completely.