Preheat the oven to 350° Fahrenheit.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, cream together butter, sugar, and brown sugar until light and fluffy.
Add in Egg and vanilla extract and mix until fully combined.
On a low speed, add in the flour mixture and mix until just incorporated.
Using a wooden spoon, stir in M&M’s. (If prefer to add in 2/3 Cup M&Ms and use the reaming 1/3 to decorate the tops of the cookies before baking)
Roll the dough into 1 to 1 ½ inch balls and place on a lined baking sheet about 2 inches apart from each other.
Bake for 9 – 11 minutes or until the edges of the cookies are lightly browned and set.
Remove the cookies from the baking sheets and allow to cool.
Enjoy!!