In a large bowl, cream together butter, brown sugar, white sugar, and peanut butter until smooth.
Beat in the eggs one at a time until well blended. Combine the flour, baking soda, and salt; stir into the creamed mixture. Mix in the oats until just combined.
Spread dough in ungreased 15x10" jelly roll pan.
Bake 20-25 minutes. Let cool 10 minutes.
Dot 1 1/2 cups of peanut butter over cookie bars by small spoonfuls. Let sit 10 minutes to allow peanut butter to soften and melt. Spread across cookie bars.
Melt chocolate chips and pour over cookie bars. Spread. Sprinkle with chopped peanuts.
Video
Notes
Cookie bars can be served immediately or after they've cooled and chocolate has had a chance to set up.