Step 1

Heat the oven to 350°F. Pan-spray or line two half sheet pans with parchment or a silicone baking mat. Mix the colored sugars together in a small bowl, and set aside.

Step 2

In a stand mixer with the paddle attachment, cream the sugar and butter on medium-high speed for 4 minutes. Scrape down the sides of the bowl, add the egg and vanilla extract, and mix for 4 minutes.

Step 3

Add the flour, salt, baking powder, and baking soda and paddle on low speed until just combined, about 20 seconds.

Step 4

Paddle in the white chocolate chips and 3 tablespoons of the color sugar blend until just incorporated.

Step 5

Using a 2 ¾ ounce ice cream scoop (or a 1/3 cup measure), scoop the dough onto prepared pans 2-3 inches apart. Sprinkle with the remaining sugar blend and bake at 350°F for 8-10 minutes.

Step 6

Cool the cookies slightly on sheet pans. Transfer cookies to a plate or to an airtight container for storage. At room temperature, the cookies will keep fresh for 3 days; in the freezer, they will keep for 1 month.