Preheat oven to 350°F/ 180°C. Line two baking sheets with parchment paper.

In a medium bowl, whisk together flour, cake mix and baking powder. Set aside.

Using a hand mixer or stand mixer, beat the butter, sugar and salt until light and fluffy. Add the egg, vanilla extract, and a few drops of the green coloring to get the desired color, mixing until almost fully combined and scraping the sides of the bowl as needed. Then add in the flour mixture and mix until almost combined. Add 1/4 cup sprinkles and pulse once or twice, then continue to stir by hand until fully combined. (It will seem crumbly, but will come together when you scoop the cookies.)

Then use a cookie scoop or big spoon to scoop the cookie dough onto the lined baking sheet. Add about 1/4 cup of sprinkles to a small bowl and press the tops of the dough balls into the sprinkles (optional,) pressing dowl just a little bit. (This will help the cookies spread a tad while baking.)

Cover and chill the cookie dough balls in the refrigerator for at least an hour (and up to 4 days) or they can be placed in a freezer-safe bag and frozen for a couple months then baked when needed.

Arrange chilled cookie dough balls 3 inches apart on the baking sheets. Bake for 12-13 minutes. The edges should be set but the centers should still look very soft. Allow the cookies to cool on the pan for about 5 minutes, then transfer them to a wire rack. Cool completely.

The cookies will stay fresh covered at room temperature for about 5 days.