Not sure how far east you're coming from as your title asks for Pittsburgh, but the Summit Diner (just off the Somerset exit - 40 minutes to an hour east of Pitt) is very good.
There's an Eat N Park less than than half a mile west of the Irwin exit (close to Monroeville/Pitt exit), and an Eat N Park Classic Diner less than 3 miles to the east of the Irwin exit.
Drew's would have been an excellent choice.
you could also get off the Turnpike at the Butler Valley Exit, which is west of Pittsburgh/Monroeville Exit. There is a classic old Diner "Venus Diner" right after the interchange heading north. If that wouldn't suit you there is also an Eat N Park down the road. These options would be more convenient with less traffic issues. Whether or not you'll find it gourmet or Chowhoundish is a totally different issue!!!
I would love to send you to Drew's Family Restaurant in Forest Hills, however you would have to get off the Turnpike (76) take the Parkway East to the Wilkinsburg Exit and then make a couple of turns to get there, but 8:00 AM is during the morning rush hour. If your arrival would be closer to 9:30 this would only take you about ten minutes, or let's be real 15 minutes.
There is an Eat and Park Classic Diner (local chain, but very good for breakfast) on Business Route 22 in Monroeville that should fit your needs. Easy off and easy on the Turnpike.