Preheat oven to 350ºF, line baking sheet with parchment paper or a light spray of cooking spray.
In a mixing bowl, cream together butter and sugars.
Add in eggs and vanilla, mix to combine
In a separate mixing bowl whisk together the flour, salt and baking soda
Fold in the M & M candy, reserving 1/4 cup to place some candies on top of the cookies if desired.
Place 1-2 inches apart on the prepared baking sheet. Bake for 10-12 minutes until cooked through and golden around the edges. Cool on a cooling rack for 5 minutes before serving.