In a large bowl, cream the butter and sugars. Add the eggs, one at a time and mixing between each addition, the vanilla, corn syrup, baking soda, and peanut butter. Mix well until smooth. Add the oats and mix well, scraping the sides of the bowl. Add the chocolate chips and mix until they are evenly distributed throughout the batter. Then add the M&M’s and mix well.
Drop the batter by the tablespoon 2 inches apart onto ungreased baking sheets. Bake at 350°F until the edges are golden brown, 10 to 12 minutes. Let cool on baking sheets for about 3 minutes before transferring to cooling racks.
Cool the cookies on a wire rack or a plate and then put into sealed containers.
These cookies will stay fresh for up to 5 days. Makes 6 dozen cookies.