For the cupcake batter and brown sugar glazed chicken: Preheat the oven to 350 degrees F. Line cupcake pans with cupcake liners (for a total of 24 cupcakes); lightly spray the liners with cooking spray.
In a medium mixing bowl, sift together the cake flour, 1 teaspoon of the cinnamon, the baking powder, baking soda and a pinch salt. In the bowl of a stand mixer with a paddle attachment, cream the butter and granulated sugar. Add the sweet potatoes and beat until smooth. Mix the vanilla extract and eggs into the sweet potato mixture, scrape down the sides of the bowl and beat until incorporated, about 1 minute. Add the dry ingredients and buttermilk to the sweet potato mixture in three parts, alternating between the dry and wet ingredients. Scrape down the sides of the bowl and beat for 30 seconds between each addition.
Scoop one scoop of the batter into each cupcake liner. Bake until the cupcakes bounce back from gentle pressure, 25 to 30 minutes. Remove from the pans and cool.
Heat the oil in a skillet over medium-high heat. Sprinkle both sides of the chicken with 1/2 teaspoon salt. Cook until golden brown and caramelized, about 4 minutes, and then flip over to cook the other side. Continue cooking to an internal temperature of 165 degrees F. Set aside to cool slightly.
In a medium saucepan over medium heat, combine the reserved sweet potato liquid, brown sugar, the remaining 2 teaspoons cinnamon and 1/2 teaspoon salt and bring to a boil. Simmer until the mixture has the consistency of maple syrup, about 5 minutes. Finely dice the cooked chicken breast and place in a medium mixing bowl. Pour the syrup over the chicken and toss to coat.
For the buttercream frosting: In the bowl of a stand mixer with a paddle attachment, beat the butter on medium speed until smooth and free of lumps. Slowly add the confectioners' sugar and cinnamon while mixing on the lowest speed. Add the vanilla and salt. Mix on medium speed until combined and smooth.
To assemble: Using a pastry bag fitted with an open tip, ice the cooled cupcakes with two rings of buttercream to form a well. Fill the well with glazed chicken and some of the syrup.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.