In a large bowl, cream together the butter, sugars, and peanut butter until smooth.
Beat in the eggs, two at a time.
Stir in the corn syrup and vanilla.
Mix in baking soda and oats until well blended.
Stir in the Reese's peanut butter cups, Reese's Pieces and peanuts.
Use an ice cream scoop to put about 2 inch balls on a cookie sheet. If you like a flat cookie, flatten the dough slightly. If you'd like the cookie thick and rounded, just leave the dough in a ball.
Bake for 10 to 12 minutes at 350 degrees.
After cooling for a few minutes on the cookie sheet, transfer them to wire racks to cool completely.
Store in an airtight container.
Drizzle the tops of these with some melted chocolate chips if you want to make them look even prettier! Simply melt 2 cups of chocolate chips in the microwave at low temperature, stirring often so the chocolate doesn't burn. Use a spoon to drizzle chocolate over top the cookies. Allow the chocolate to set completely before storing them.