This recipe is SOOO easy and pretty self explanatory! I don't think you can go WRONG using any kind of boxed brownies...but I have to say that my favorite is DUNCAN HINES boxed brownies. They're usually cheaper than Ghirardelli - but just a TAD bit better, in my opinion. But hello, Ghirardelli, is GHIRARDELLI, which is super yummy too.
To insert the Reese's (you'll need 3 packages of two for a 9x9" pan) - just make the boxed brownies per directions on box. Poor batter into a pam'd pan, level out. Then, press each Reese's cup into the top of the batter like this....Bake as directed on box!
Add icecream, Hershey's syrup and anything else your heart desires!