Add water and sugar to the mixing bowl of your stand mixer. Swirl to dissolve the sugar. Then add the yeast. Allow to bloom and become foamy (about 5 minutes).
Add in three cups of flour, the salt and butter. Mix on medium low until completely combined. Then add remaining flour, half a cup at a time. Continue to mix until dough starts to pull away from the sides of the bowl.
If your mixer has a dough hook, remove the mixing paddle and install the dough hook. Then knead the dough for about 5 minutes on medium. Once the dough is in a nice ball, remove the mixing bowl from the stand mixer and cover with plastic wrap. Allow to rise until double in size (about 2 hours) in a warm spot. If it is colder where you are, place the bowl in your oven with just the oven light on.
Once the dough has doubled in size, punch it down and remove it from the bowl on to a lightly floured surface. Split the dough into two equal pieces and gently knead into two loaves.
Add the dough to two parchment paper lined bread pans. Again cover with plastic wrap and let rise for another hour.
Preheat the oven to 350degF. Remove plastic wrap from the loaf pans and bake for 35 minutes. Remove from the loaf pans using the parchment paper and allow to cool on a baking rack before slicing.
Keyword bread, sandwich bread, white bread, yeast bread, yeast dough