Preheat the oven to 350 °F. Line a cookie sheet with parchment paper or non-stick baking mats.
In a large bowl, combine the butter, peanut butter, and sugars. Mix well.
Add 1 egg at a time, scraping the dough from the edges of the bowl in between. Add the vanilla.
In a second large bowl, add the oats, flour, baking soda, and salt. Mix until combined.
Add the dry ingredients to the bowlwith the wet ingredients, and mix until they are just combined.
Fold in the M&M’s, chocolate chips, and butterscotch.
Portion the dough into 1/4th cup-sized balls, and place htem 4 inches apart on the prepared cookie sheet.
Bake for 8-10 minutes. Be careful not to overbake!
As soon as the cookies are removed from the oven, gently push them down with the back of a spatula. Let them stand for 3 minutes before transferring them to a wire rack to cool completely.
Store in large resealable plastic bags or an airtight container for up to 1 week.