Preheat oven to 350° F or 180° C.
Prepare one 12 capacity muffin or cupcake pan with baking liners or non stick spray and set aside.
In a large bowl, whisk together all the dry ingredient (flour, baking powder, salt, cinnamon, and nutmeg) and set aside.
In a separate bowl, Mash the sweet potato to a smooth consistency or you can leave some chucks to give it texture. Add the wet ingredient (eggs, sugar, yogurt, vegetable oil, and vanilla extract) to the mashed potatoes and mix until well combined. For a smoother consistency, the sweet potato and the all the wet ingredients can be mixed with a blender or hand mixer.
Add the sweet potato mixture to the dry mixture and stir together until combined but do not over mix. The batter will look lumpy and that is ok because the lumps will disappear during baking. There should not be any patches of flour in the batter as well.
Pour into the prepared muffin pans and bake in the preheated oven for 18- 20 minutes or when toothpick inserted to the center of the muffins comes out clean and dry.
Bring the muffins out of the oven and allow to cool on a cooling rack or wire.
Serve and enjoy.