Preheat the oven to 350 degrees. Line cookie sheets with parchment paper or non-stick baking mats.
In a very large mixing bowl, combine the eggs and sugars. Mix well. Add the salt, vanilla, peanut butter, and butter. Mix well. Stir in the m&m's, chocolate chips, baking soda, and oatmeal.
Drop by tablespoons 2 inches apart onto the prepared cookie sheets.
Bake for 8-10 minutes. Let stand for about 3 minutes before transferring to wire racks to cool.
Recipe by the ringers at https://www.theringers.co/2013/12/the-12-days-of-cookies-day-5-2/