Preheat oven to 350 degrees. Use parchment paper or a silpat mat to line a baking sheet.
Cream the butter, sugar and powdered in a stand mixer until light and fluffy (about 2-3 minutes). Scrape the sides of the bowl to make sure all ingredients are blended.
Add in the egg and vanilla and beat until combined.
Add in flour, salt and baking powder. Mix until all combined.
Scoop out dough and roll into balls. Scoop out 1 TBSP dough for smaller cookies (or 1/4 cup dough for BIG cookies). Place dough balls on prepared pan (12 cookies to a pan if smaller cookies) and slightly flatten with your hand to about 3/4 – 1 inch thick.
Bake for 8-9 minutes. Cool cookies cookie sheet for 10 minutes before removing to cooling rack. NOTE: If you decide to make the bigger cookies, you’ll need to bake them for 13-15 minutes.
While cookies are cooling, make the frosting.
CAKE BATTER FROSTING DIRECTIONS
In stand mixer, cream butter for about 1 minute until smooth
Add in the cake batter extract, powdered sugar and heavy cream and mix on high for about 3 minutes until smooth. If the frosting is too thick, add more heavy cream a teaspoon at a time to get the consistency you are looking for. If frosting is too thin, add more powdered sugar.
Remove and save 1/4 cup of the white frosting.
Add just a bit of green food coloring to the remaining frosting in the bowl and mix until you get the shade of green that you are looking for.
Put the frosting in a piping bag OR you can put the frosting in a gallon size Ziploc bag and cut off one corner of the bag. Use the frosting bag to pipe frosting in a spiral on top of the cooled cookies.
Put the set aside white frosting in a piping bag with a small round tip (or cut the corner off a Ziploc bag) and pipe two curved lines away from each other on top of each cookie to resemble tennis ball lines.