Preheat the oven to 375°F/190oC. Line two cookies with parchment.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, cream together the butter, sugar, and cream cheese (if you're using it) until light and fluffy- about 2 to 3 minutes.
Beat in the vanilla extract, and the egg; scrape the sides and bottom of the bowl.
Add the flour mixture, and mix at low to medium speed until the mixture is evenly moistened.
Place the 3/4 cup of sprinkles in a large plastic bag, or in a shallow pan. Scoop the dough by tablespoonfuls into the sprinkles, rolling them in the pan or gently shaking them in the bag to coat them with the sprinkles.
Place on the prepared baking sheets, leaving 2" between them. Using a flat-bottomed glass, or the palm of your hand flatten the cookies to about 1/4" thick.
Bake for 10 to 12 minutes — 10 minutes for softer cookies, 12 minutes for crunchier. The edges of the cookies will just barely begin to brown.
Remove from the oven and cool on the pan for 5 minutes, before transferring to a rack to finish cooling completely.