In a large mixing bowl, beat together the butter and granulated sugar until creamy (about 2-3 minutes).

Add in the egg and vanilla extract. Beat in until fully mixed.

In a separate bowl, whisk together the flour, baking powder, corn starch, baking soda, and salt.

Add the dry ingredients to the wet ingredients and beat just until combined, but be careful not to over-mix.

Remove 3 tablespoons of the rainbow sprinkles and set aside for now. Stir in the remaining rainbow sprinkles.

Line two baking sheets with parchment paper.

Using a 2-tablespoon sized measuring spoon, scoop cookies. Shape cookies into round balls. Place the cookies close together on the baking sheet to fit into the freezer.

Using the remaining 3 tablespoons of rainbow sprinkles, press sprinkles into the top of each raw cookie ball.

Place baking sheet in freezer for 15 minutes before baking. It’s important to bake the cookies from frozen, so they don’t spread too much during baking.

Preheat oven to 350 degrees F.

On parchment paper lined baking sheets, place cookies about two inches apart.

Bake cookies for 10-12 minutes from a frozen state. Cookies are done once edges are slightly golden but top of cookies still look wet. If baking both trays at the same time, you may need to add an additional 2 minutes of baking time. Let cookies cool on baking sheet for about 10 minutes before moving.

Store cookies in a sealable container for up to two weeks at room temperature.** I’d recommend eating them within a week though or freezing them to enjoy later.