01 -
Preheat oven to 350°F (175°C). Line two baking sheets with parchment paper.
02 -
In a bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
03 -
In a separate bowl, using a hand mixer or stand mixer fitted with the paddle attachment, beat butter and both sugars for 1-2 minutes, until light and fluffy. Add egg and vanilla extract, mixing until combined, scraping the sides of the bowl as needed.
04 -
On low speed, add the flour mixture to the wet ingredients and mix until just combined.
05 -
Gently stir in M&M's and white chocolate chips. Place the sprinkles in a shallow bowl.
06 -
Scoop balls of cookie dough, between 1½ and 2½ tablespoon portions. Gently press the top of each ball into the bowl of sprinkles. For slightly thicker cookies, chill the dough balls in the refrigerator for about 20 minutes (optional).
07 -
Place dough onto prepared baking sheets leaving 2-5 cm between cookies for spreading. Form the dough balls higher rather than wider for optimal thickness.
08 -
Bake for 8-11 minutes, until the edges of the cookies are set but the center is still slightly underdone for a soft texture.
09 -
Place the baking sheets on wire racks and allow the cookies to cool completely. If desired, press additional M&M's and/or chocolate chips onto the top of the cookies while still warm.