These are EASY Toffee Bars with peanut butter inside! They have a peanut butter cookie base with a chocolate frosting and lots of toffee bits. These easy bar cookies are perfect for any occasion, especially when you want to ship cookies!
Preheat oven to 350°. Line a 9×13” baking dish with foil and spray with cooking spray.
Beat butter, sugar, peanut butter, and egg yolk on medium-high speed in an electric mixer until smooth. Scrape down the sides of the bowl. Add the flour, oats, and salt and beat on low until just combined.
Press the mixture into the bottom of the prepared pan. Bake 15-20 minutes until the top is golden. (Be careful not to over bake!)
Remove the pan from the oven and scatter the chocolate chips evenly over crust. Place pan back in oven for 1 minute. Remove the pan and spread the melting chocolate chips evenly with an offset spatula. Sprinkle the toffee bits evenly over the top and gently press them into place.
Set on a rack to cool until the chocolate has hardened, at least 2 hours. Remove from pan using foil. Cut into squares while room temperature. Store in the refrigerator for maximum freshness. (Bars can also be frozen for later use.)