For the cake batter: Preheat the oven to 325 degrees F; line cupcake pans with 24 cupcake liners.
In a medium bowl, combine the pastry flour, cornstarch, cinnamon, baking powder, nutmeg, baking soda and salt and set aside. Using an electric mixer with a paddle attachment, cream the butter and granulated sugar until light and fluffy; scrape down the sides of the bowl. Add the eggs one at a time, beating well after each addition; mix in the vanilla. Alternately add the flour mixture and the buttermilk, starting and ending with the flour mixture and beating well after each addition.
Spoon the batter into the liners, filling them about halfway, and add 1 teaspoon of cherry filling in the center of each. Bake until an inserted toothpick comes out clean, about 25 minutes. Let the cupcakes cool completely before frosting.
Raise the oven temperature to 350 degrees F for the crumble.
For the oatmeal crisp crumble: In a medium bowl, combine the all-purpose flour, rolled oats, brown sugar, cinnamon and nutmeg. Cut in the cold butter until the mixture gets crumbly. Spread the mixture on a baking sheet and bake for 15 minutes. Let cool.
For the cinnamon buttercream: In the bowl of an electric mixer with a paddle attachment, beat the shortening and butter on medium speed until creamy and smooth. Add the vanilla and beat for 2 minutes. Add the confectioners' sugar and cinnamon and beat for 1 minute. Add 1/4 cup water and beat until creamy and smooth.
To assemble: Frost the cupcakes with the cinnamon buttercream and garnish with the oatmeal crisp crumble.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.