1tablespoonunsalted buttersoftened to room temperature
Preheat oven to 350F. Spray one 9-by-5-inch loaf pan or two 8-by-4-inch loaf pans, or a 12 cup muffin tin with cooking spray or grease and flour; set aside.
To Cook Potatoes (skip if using canned sweet potato): Scrub potato thoroughly and prick several times with a fork. Place on a plate. Cook on full power in the microwave for 5 minutes. Turn over and continue to cook for 5 more minutes. Remove from oven and allow to cool slightly. Slice in half and scrape flesh from the inside of the potato into a large bowl.
In the same large bowl, add all the wet ingredients to the sweet potatoes. Mix to combine. add all the dry ingredients and mix with a spoon just until combine.
Pour batter out into prepared pan(s), smoothing the top lightly with a spatula. Bake for 60 to 70 minutes for a 9x5 pan, top is golden, or toothpick inserted comes out clean. If making in muffin pans bake only 20 minutes. Cool for at least 20 minutes before icing.
To make cream cheese icing:
Beat the softened cream cheese and butter together until soft and creamy. Add powdered sugar and beat until thick and combined. Add milk and beat on medium speed for 2 more minutes. Spread or drizzle the frosting on the cooled bread.