Preheat the oven to 350°F (180°C). Line a cookie sheet with a silicone baking mat or parchment paper. Set aside.
In a bowl, cream together the butter and sugar until light and fluffy. It typically takes about 2 minutes.
Next, add in the eggs and cake batter flavoring. Once mixed, add in the flour, baking powder and sprinkles. Mix until thoroughly combined.
Divide the dough into 1 ½ Tbsp portions, roll into a ball and flatten slightly before arranging on the prepared cookie sheet.
Bake for 9-11 minutes or until the centers of the cookies have puffed up and are no longer glossy.
While the cookies are cooling, make the frosting, by whipping the butter and cream cheese until smooth.
Add the powdered sugar, one cup at a time, mixing each time until it is fully incorporated.
Add in the cake batter flavoring and mix to incorporate. Add milk a tsp at a time until you've reached your desired consistency, if needed.
Add the frosting to a piping bag fit with a round piping tip. Pipe on the cookie in a spiral, starting in the center and working your way out.
Sprinkle some extra sprinkles on top and serve warm.