In a large bowl add flour, baking powder and salt. Whisk together and set aside
In the bowl of an electric mixer add butter and beat until smooth.
Add sugar and blend until fully combined and fluffy.
Add egg and vanilla and blend.
While mixing, slowly pour in the bowl of flour.
Mix until dough forms and starts pulling away from the sides of the bowl.
Add 2 tablespoons sprinkles and blend just until incorporated.
Scoop the dough out onto a work surface and form into two large balls. Avoid working the dough with your hands too much, as this may cause the colors of the sprinkles to bleed.
Lay a large piece of plastic wrap on your work surface. Place a ball of dough on top and press the dough down just a bit to flatten. Top dough with another sheet of plastic wrap, then roll out the dough (between the two sheets). This method eliminates the need for adding extra flour (as might traditionally be done).
Once the dough is your desired thickness (about 1/3 of an inch) remove top layer of plastic wrap and sprinkle the entire top surface of the dough with sprinkles. Gently roll your rolling pin over the sprinkle covered dough to embed the sprinkles into the dough.
Cut out cookies as desired. I used a large knife to cut the dough into 1"x4" strips.
Place similar sized cookies together (at least 1/2 inch apart) on a baking sheet lined with parchment paper or a silpat type liner. Place entire baking sheet of unbaked cookies in the fridge for 15 minutes or freezer for at least 5 minutes. This step helps prevent spreading.
Bake 8-10 minutes in a preheated 350*F oven.
Cool on the baking sheet for 1-2 minutes, and then move to a cooling rack.
Once fully cool, store the cookies in a sealed container. The baked cookies will remain fresh (when stored well) for at least a week.