In a large mixing bowl, mix the butter, sugars, eggs, vanilla, salt, baking powder and baking soda with an electric mixer until smooth.
Stir in flour and M&Ms with a wooden spoon to combine.
Shape dough with hands into golf ball-sized dough balls and place a couple inches apart on greased cookie sheets.
Bake for 13-15 minutes or until edges are light brown.
Rotate cookies on racks every six minutes while baking.
Notes
NOTE: There are times when I’m making a double batch of this recipe where I have to add an additional quarter to half cup of flour in order to be able to roll the dough into balls. If the dough gets too sticky. Add a little flour to the batter.