They sell an assortment of freshly baked breads, cookies, and other desserts as well as making sandwiches to order. Bags of various mixes including trail mix ("Pittsburgh Pothole Crunch), brownie mix, and pancake mix are also available. They also sell some Penn's Corner CSA items including their delicious (and expensive salsa).
I can vouch for the oatmeal cookies which are delicious. The Port Authority (portobello veggie sandwich, and the Baja turkey were both good. Service is a bit slow, but they're new so I imagine it will improve with time.