Place the sweet potatoes in a baking tray.
Apply some oil all over and prick with a fork. Place in a preheated oven at 425 F for 45-50 minutes, till fork tender.
Remove the sweet potato and peel completely.
Mash using a fork and set aside.
In a bowl add warm water and mix in sugar and salt.
Add active dry yeast and stir well. Cover and place in a warm spot for 10-15 minutes, till frothy.
In the base of a stand mixer or a large bowl add flour, salt, mashed sweet potato and unsalted butter.
Add the frothy yeast mixture.
Place the bowl in the stand mixer and start kneading with a hook attachment.
Knead well till the dough forms and about 5 minutes after.
Shape the dough into a round. Apply oil in the bowl and place the dough ball in it. Let the dough rise for 60-70 minutes in a warm place.
Once the dough doubles in size, punch it down.
Remove and lightly knead for a couple minutes.
Spread the dough on a baking tray into a rectangle of about 8 inches width.
Roll into a tight roll along the shorter side.
Grease a 9* 4 inch bread pan and place the dough log in it. Cover and let rise for another hour in a warm place.
Once the dough almost reaches the top of the pan, spray some oil based spray.
Bake for 22-24 minutes in an oven preheated to 425 F. Remove pan from the oven.
Let the bread cool a little and transfer to a baking tray or cooling rack.
Once it cools, slice the bread into slices of desired thickness and enjoy.