Cream butter, sugar, vanilla, and eggs in a mixing bowl.  

In a second bowl, whisk together flour, baking powder, and salt.

Slowly add the flour to the butter and sugar mixture until a cookie dough is formed.  

Fold in sprinkles.

Cover the dough with plastic wrap and chill the dough in the refrigerator for at least 1 hour, preferably overnight.  Chilling the dough will help make the cookies chewy and prevent them from spreading.

When it is time to bake cookies, preheat the oven to 400 f.

On a cutting board, dusted with flour, roll the cookie dough into 1/2 sheets.  Dust flour onto the dough if it is sticky.  Cut out cookie shapes and place them onto a baking sheet lined with parchment paper.  Make sure that the cookies are at least 1 inch apart.

Bake cookies for 8 minutes.  They will still look light when you remove them from the oven.  

Let the cookies cool slightly before transferring them to a cooling rack.

Cookies should be cooled completely before decorating.