What exactly is Grana Parmesan cheese?

Never heard of that…. I’m sure any parmesan is fine for a recipe.

google:

The authentic cheese from Parma that inspired the word parmesan is named Parmigiano- Reggiano. Real Parmigiano-Reggiano can only be made in a defined region of northern Italy that includes the counties of Parma and Reggio Emilia. Eating a superb Parmigiano-Reggiano borders on privilege; there is grandeur in this cheese, as well as delight.
A similar cheese named Grana Padano, also from northern Italy, is less well known in the US but outsells Parmigiano-Reggiano by 10 to 1 in Italy. Just like with Parmigiano-Reggiano, savoring an outstanding Grana Padano is also a heavenly experience.
Cistercian monks first created Grana Padano in the 11th century. Parmigiano-Reggiano, originally a copy of “Grana”, debuted about two hundred years later. Today, each cheese is made according to its ancient origin. Each cheese today is still identical to how they were centuries ago, having the same appearance, the same extraordinary fragrance, made in the same way, in the same places, with the same expert ritual techniques.

(just use parmigiano-reggiano)

Wow—Terrific response. I was advised at Whole Foods, also, to substitute Parmigiano-Reggiano for the Parma. I have been able to get the Parma at Whole Foods in the past, and I guess they have it occasionally.

BTW, I am using it for a great salad from “Jamie’s Italy” by Jamie Oliver. The salad consists of arugula and sliced radicchio, toasted pine nuts, finely shredded Parmesan, freshly ground pepper & salt, and a dressing of olive oil and balsamic vinegar. The latter is 3 parts olive oil to 1 part balsamic vinegar.

Thanks for your answer!