Beat butter, white sugar, brown sugar and vanilla until fluffy.
Add in eggs and beat well.
Slowly add in flour, salt and baking soda, then mix until well blended.
Add in chocolate chips and M&Ms.
Spread into 9x13" pan or pat onto a 12" Pizza Pan
Bake at 375 for 20-25 minutes.
Frost with buttercream or store-bought frosting and Enjoy!(I just beat together 1 stick of butter (softened), 1/2 teaspoon vanilla, and 2 cups powdered sugar, then add a few tablespoons of milk until it's at desired thickness.)