If you haven't cooked the sweet potato yet, peel and slice it into 1-inch chunks. Arrange a steamer basket into a small sauce pan and fill it with roughly an inch of water. Pour the sweet potato chunks into the steamer basket, keeping them out of the water, and bring the water to a boil. Cover the pot and lower the heat so that the water is still simmering, and cook until the sweet potatoes are fork-tender, about 10 to 15 minutes. (The smaller you cut the sweet potato, the faster it will cook.)
Once you have cooked sweet potato, mash it with a fork and measure out 1 cup of mashed potato to use in this recipe. (Save any extra cooked potato to add into a sweet potato smoothie!)
Preheat the oven to 350ºF and grease a mini muffin tin. Or, you can line a standard muffin with muffin cups, if you prefer to make larger muffins.
In a large bowl, combine the sweet potato, oat flour, almond butter, maple syrup, baking powder, cinnamon, and salt and stir until smooth. Fold in chocolate chips, raisins, or chopped walnuts, if desired.
Use a cookie scoop or heaping tablespoon to drop the dough into the mini muffin tin. I typically get about 22 mini muffins with this recipe. For larger muffins, use 1/4 cup measure to scoop the dough into the muffin cups. You should get 10 to 11 larger muffins.
For mini muffins, bake at 350ºF for 18 minutes. For full-sized muffins, bake for 25 minutes instead.
Allow the muffins to cool completely before serving. They should last on the counter for up to 2 days, but for a longer shelf life I recommend storing them in the fridge in an airtight container for up to a week. You can also freeze them for up to 3 months!