Preheat the oven to 350F degrees. Line two baking sheets with parchment paper, set aside.
In a large bowl, whisk together flour, baking powder and baking soda with a fork or whisk.
In the bowl of an electric stand mixer (or using a handheld electric mixer) mix together softened butter, sugar and softened cream cheese until fully combined.
Next, mix in egg and vanilla extract.
Slowly add in the flour mixture (a little at a time) and mix until combined - dough will be sticky.
Cover bowl with plastic wrap and place it into the refrigerator for a minimum of one hour.
When dough is ready, place nonpareils in a shallow bowl. Scoop dough out in about 1 ½ tablespoon balls (I like to use a medium spring-loaded cookie scoop).
Roll the cookie dough balls into the nonpareils until thoroughly coated. Continue with the rest of the cookie dough balls.
Place cookie dough balls about 2-inches apart on the prepared baking sheets.
Gently flatten the cookies with the bottom of a measuring cup or the bottom of a small glass until the dough is about half an inch thick. Place one cookie sheet into the fridge to keep chilled.
Place the other baking sheet into the oven to bake. Bake for about 10-12 minutes. Cookies may appear slightly under baked. Cookies will continue to bake once removed from the oven.
Baking one cookie sheet at a time will help ensure even baking.
Let cookies cool for about 5 minutes then transfer to a wire rack to cool completely. Continue with baking the second sheet of cookies.
Notes
Make sure to chill the dough for at least an hour. This is essential.
You can swap out the nonpareils for rainbow sprinkles.
These baked cookies can be frozen for up to 3 months in a freezer bag.
Recipe can easily be doubled.
Make sure the butter is softened (not melted) when using.
Is using unsalted butter, add about 1/2 teaspoon of salt to the dough.