Pre-Heat Oven to 350°
Line cookie sheet with parchment paper
In the bowl of your stand mixer fitted with the paddle attachment or in a mixing bowl with electric mixer, mix the butter and both sugars together for 2 minutes on medium speed until light and fluffy. Add in the egg, vanilla, salt, and baking soda and continue mixing for 2 minute until smooth, scraping the sides of the bowl as necessary
Reduce mixer speed to low , slowly add flour
Add Chocolate Chips and half of the M&M's
Scoop Cookies on to baking sheet -bake for 10-12 minutes until golden brown
Remove from Oven , well still warm , press remaining M&M's into tops of cookies.
Allow to cool for 3-5 minutes on pan and then move to cooling rack.
Cool and serve.