Preheat the oven to 375°F. Line two baking sheets with parchment paper and set aside.
In a large bowl, cream together the butter and sugars. Mix for 1 minute, or until creamy and fluffy. Add the eggs and vanilla and mix just until combined. Next add the flour, baking soda and salt and mix just until combined. Do not over mix.
Fold in the chocolate chips and M&M’s. Refrigerate dough for 15 to 60 minutes if time allows.
Using a large cookie scoop (about 3 Tablespoons), scoop the cookie dough onto the baking sheet about 2 inches apart. Place extra chocolate chips or M&M’s on the top of the cookies if desired.
Place pan in oven and bake for 7-10 minutes, or until the edges are barely golden brown. Allow cookies to set on pan for 2-3 minutes, and then remove to a cooling rack to cool.
Once the cookies are cooled, store in an airtight container for up to 3 days. Freeze for up to 3 months.
M&M's: Feel free to replace with rainbow M&M's or any other seasonal variety. To store: These cookies will stay fresh in an airtight container in the fridge for up to 3 days. You can keep them covered on the counter the day you make them, just make sure to transfer them into the fridge before you go to bed at night.To freeze: Once completely cooled, place in a freezer-friendly bag or airtight container and freeze for up to 3 months.