Preheat oven to 350° F.
In the mixing bowl, mix butter, egg, vanilla and sugar together until smooth.
In a separate bowl combine baking powder with the flour and then add a little at a time to the wet ingredients. The dough will be stiff. DO NOT CHILL THE DOUGH.
Scoop into tablespoon sized balls and place on a nonstick pan.
Slightly flatten each ball with a spoon/spatula.
Bake at 350 for 8-10 minutes.
Remove from oven and place sprinkles on the cookies. They should stick due to the cookies being warm.
Let the cookies cool on the pan until firm enough to transfer to a cooling rack.
Serve & enjoy!