In a medium mixing bowl, combine flour, baking powder, baking soda, cream of tartar and salt. Set aside.
In a large mixing bowl or stand mixer, beat butter and sugar on high for 3 minutes, until light and fluffy.
Add egg and vanilla and beat until just combined.
Gradually add dry mixture to wet mixture until combined. Fold in sprinkles.
Using a tablespoon, roll large dough balls or use a cookie scoop. Place on a parchment lined baking sheet and refrigerate covered 2 hours.
Preheat oven to 350°F. Space dough balls 3" apart yielding 12 cookies per each large baking sheet.
Bake 12 minutes. Cookies will appear light in color, soft in the center and underbaked.
Allow cookies to cool 1 minute. Transfer to a wire rack to cool completely.