1/2 cup coconut oil {or butter}
1/2 cup packed brown sugar
1/2 cup granulated sugar
1 egg + 1 egg yolk {save the white for the frosting!}
1/4 teaspoon vanilla bean paste {or 1/2 teaspoon extract}
1/2 cup cooked, pureed sweet potato
2/3 cup all purpose flour
2/3 cup white whole wheat pastry flour
3/4 teaspoon baking powder
1/4 teaspoon baking soda
1/4 teaspoon salt
1/2 teaspoon cinnamon
1/4 teaspoon nutmeg
1/4 cup milk

For the frosting:

1 cup packed brown sugar
1/2 cup granulated sugar
1/3 cup cold water
1/4 cup mini marshmallows
1 egg white
1 large pinch cream of tartar
1/4 teaspoon vanilla bean paste {or 1/2 teaspoon vanilla}
1/4 cup chopped & toasted pecans, optional

Directions:

Preheat oven to 350 degrees. Line a muffin tin with 12 paper liners and set aside.
In a large bowl, cream coconut oil with sugars. Stir in egg, egg yolk, vanilla bean paste and sweet potato. Scrape sides and whip until light and fluffy. In another large bowl stir flours, leavenings and spices together using a fork or whisk. With the mixer on low, alternate mixing in dry ingredients with milk, starting and ending with dry. Once ingredients are all incorporated, mix the batter together by hand to ensure everything is mixed evenly. Spoon into prepared tins and place into hot oven. Reduce temperature to 325 and bake 18-22 minutes or until toothpick comes out clean after being inserted. Set aside to cool.
For the frosting, place brown sugar, granulated sugar and water into a small pot. Stir to moisten sugar and place over medium high heat. In a large bowl, whip egg white and cream of tartar until stiff peaks form. Once the sugar dissolves in water and starts to bubble {not too violently} time 1 minute. After this, remove from heat and stir in marshmallows. Once those have melted, slowly pour the hot sugar mixture into the egg whites while whipping with a hand mixer on medium to high speed. Continue whipping for 3-5 minutes or until frosting becomes very thick and holds its shape. Stir in vanilla bean paste. Immediately scoop this frosting into a piping bag and frost all cupcakes. Top with chopped and toasted pecans, if desired.