Preheat oven to 375 degrees Fahrenheit.
In a KitchenAid stand mixer, begin to cream butter, granulated sugar, and brown sugar on medium speed for 1 minute.
Then add the vanilla extract and eggs (one at a time). Mix until incorporated about 1 minute.
Add the 2-¼ cup all-purpose flour, baking soda, and salt. Add to the stand mixer, and mix for 30 seconds or until well incorporated.
Add the chopped chocolate and M&M's; mix until just incorporated. Scrape down the sides of the bowl and mix one last time for about 5-10 seconds.
Using a medium cookie scoop, begin scooping dough and placing on an ungreased cookie sheet.
Bake for 10 minutes, then remove from the oven and let sit on the hot cookie sheet for 5 minutes, then transfer to a wire rack to cool. Repeat until all the cookie dough has been made.