I read a great article on rocotos recently. Appearently, the best thing to do it to leave it on the plant until you are ready to eat it (make sure it's ripe). Their best flavor is when you use them immediatly after picking them. Also, be sure to remove the seeds because they are extremely hard and it will be like eating small rocks.
As far as what you can do with them...
"You can barbecue it, boil it, broil it, bake it, saute it. Dey's uh, rocoto-kabobs, rocoto creole, rocoto gumbo. Pan fried, deep fried, stir-fried. There's pineapple rocoto, lemon rocoto, coconut rocoto, pepper rocoto, rocoto soup, rocoto stew, rocoto salad, rocoto and potatoes, rocoto burger, rocoto sandwich. That- that's about it. "
I too am growing these. Haven't gotten one to pollinate yet....but the plants are getting around 2.5 feet and the flowers are everwhere.