Preheat oven to 350 °F.
Spray two 9-inch cake pans with non-stick spray, line the bottom with parchment circle, and spray the top of the parchment with non-stick spray.
Ina separate bowl, combine flour, baking powder, baking soda, salt, cinnamon, nutmeg, and whisk until combined.
In another bowl, whisk oil, buttermilk, sugar, eggs, vanilla, and sweet potatoes.
Slowly add the wet ingredients to the dry ingredients and mix.
Divide the batter between the prepared pans and bake for 30-35 minutes or until an inserted toothpick comes out clean.
Allow the cakes to cool for 10 minutes in their pans and then remove the cake layers from their pans and cool completely on a wire rack.
Frost with brown butter cinnamon frosting.