In a medium bowl combine flour, corn starch, baking soda, and salt. Set aside.
In bowl of stand mixer fitted or a large bowl using hand mixer, cream together the butter, cream cheese, and sugar until light and fluffy.
Add in eggs and vanilla and blend till combined until light and fluffy, scraping the bowl sides as needed.
Add the flour mixture gradually and mix together on low/medium speed until combined.
By hand, add in 1/2 cup of sprinkles and gently fold into dough.
Refrigerate dough for two hours before baking.
When dough is done chilling, preheat oven to 350 degrees. Line baking sheets with parchment paper or spray with non-stick cooking spray.
Pour the remaining 1 cup of sprinkles into a medium bowl, and roll tablespoon sized balls of dough into the sprinkles.
Place the cookies onto prepared baking sheet, spacing 2 inches apart.
Gently press a large red candy heart in the center of the dough ball.
Bake for 9-11 minutes. The cookies will not turn golden brown, and will still look a little wet when they come out of the oven. This is normal.
Allow cookies to cool on baking sheet for 3-5 minutes before moving to a wire rack to cool completely.