Preheat a convection oven to 325 degrees F (165 degrees C). See note for non-convection oven. Line baking sheets with parchment paper.
In a large bowl, cream together the shortening, white sugar and brown sugar until smooth. Mix in peanut butter until well blended. Scrape down the sides of the bowl with a plastic scraper between additions. Add eggs 5 or 6 at a time, mixing well after each addition. Scrape down bowl, and mix for a minute. Combine the flour, baking soda and salt; gradually mix into the dough until fully incorporated. Scrape down the sides of the bowl one more time, and be sure the bottom has mixed evenly.
Scoop out dough using an ice cream scoop, or roll into 2 inch balls. Place cookies 3 inches apart on the prepared baking sheets. Press down lightly with a fork to make a criss-cross pattern.
Bake for 7 minutes in the preheated oven, until the edges are lightly toasted. Allow cookies to cool on the baking sheet for at least 5 minutes so they do not crumble.
