Bake the Sweet Potatoes: Preheat the oven to 400°F. Cut the sweet potatoes in half lengthwise and place them cut side down on a baking sheet. Roast for 15 minutes, then flip and continue baking for another 15 minutes, until the tops are browned and a fork easily pierces them. Remove from the oven, let cool, then scoop out the soft flesh, discarding the skins.
Prepare the Loaf Pan & Oven: Lower the oven temperature to 325°F and grease a 9 x 5-inch loaf pan with butter or nonstick spray.
Cream the Butter & Sugar: In a large mixing bowl, use an electric mixer to beat the sugar and butter together until the mixture is light and fluffy. Add eggs one at a time, mixing well after each. Stir in the vanilla extract and set aside.
Mix Wet Ingredients: In a separate bowl, mash the roasted sweet potatoes with the milk, cinnamon, and nutmeg until smooth.
Combine Dry Ingredients: In another bowl, whisk together the sifted flour, baking powder, baking soda, and salt.
Combine Everything: Gradually add the mashed sweet potato mixture to the creamed butter mixture, stirring to combine. Then, slowly fold in the dry ingredients, mixing until just incorporated.
Bake the Bread: Pour the batter into the prepared loaf pan, smoothing the top. Bake for 1 hour, or until a toothpick inserted into the center comes out clean.
Cool & Serve: Let the bread rest in the pan for 15 minutes, then carefully transfer it to a cooling rack to cool completely. Slice and serve with Cinnamon Honey Butter for extra flavor.