01 -
Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.
02 -
In a bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
03 -
In a separate bowl, use a hand mixer or stand mixer to beat the butter and both sugars until light and fluffy, about 1-2 minutes. Add the egg and vanilla extract, mixing until combined. Scrape the sides of the bowl as needed.
04 -
On low speed, add the flour mixture to the butter mixture and mix until just combined.
05 -
Gently stir in the M&M's and white chocolate chips. Place the sprinkles in a shallow bowl.
06 -
Scoop balls of cookie dough, about 1½ to 2½ tablespoons each. Gently press the top of each ball into the bowl of sprinkles. You can bake the cookies right away or chill the dough balls in the fridge for about 20 minutes for slightly thicker cookies.
07 -
Place the dough balls onto the prepared baking sheets, leaving an inch or two for spreading. Make sure the dough balls are mounded higher rather than wider. Bake for 8-11 minutes, until the edges are set but the center is still slightly underdone.
08 -
Place the baking sheets on wire racks and allow the cookies to cool completely. If desired, press some M&M's and/or chocolate chips onto the top of the cookies while they are still warm.