Add butter and both sugars to a stand mixer with the paddle attachment.
Add in vanilla and egg. Mix until combined. Make sure to scrap the sides of the bowl throughout.
Meanwhile add flour, pudding mix and baking soda to a medium bowl. Whisk to combine.
Slowly add in the dry ingredients to the wet in two parts.
Fold in chocolate chips and M & M's.
Portion out 12 cookies and place them on a plate. Place in the fridge for at least 2 hours or overnight. Note: You must chill dough. If not the cookies will spread!
Preheat oven to 350 degrees.
Place in the oven and bake for 10-12 minutes.
Allow cookies to cool for a couple of minutes before transferring them to a wire rack to cool completely.