Preheat the oven to 375° and have ready a baking sheet lined with either parchment paper or a silicone baking mat.
In a medium-sized mixing bowl, whisk together cake flour, baking powder, and salt. Set aside until ready to use.
Add the butter and the shortening to the bowl of stand mixer fitter with a paddle attachment. If you do not have a stand mixer, use a large mixing bowl and a handheld mixer. Beat on medium-high speed to combine. Add the granulated sugar, and mix on medium-high speed for 3-4 minutes until lightened in color and fluffy. Scrape down the sides of the bowl and the egg one at a time, mixing well after each addition. Scrape down the sides and bottom of the bowl once more. Add the vanilla and mix to combine.
Add the dry ingredients and mix on low until fully incorporated.
Scoop heaping tablespoons of dough and roll into a ball. Place on baking sheet about 1-2" apart and bake for 14 minutes, just until the bottom edges are lightly tinging with gold. Remove from the oven, transfer to a cooling rack, and allow the cookies to cool completely before frosting.
Add all of the ingredients to the bowl of stand mixer fitted with a paddle attachment and begin mixing on low. If you do not have a stand mixer, use a handheld mixer and a large mixing bowl.
Once the sugar is mostly mixed in, increase the speed to medium-high, and blend until smooth and creamy.
Add a dollop of frosting to the top of each cookie and spread to the edges using either the back of a spoon or a small offset spatula. Top with sprinkles, serve and enjoy!
The Anthony Kitchen