Preheat oven to 400 degrees F. Line a baking sheet with foil and set aside. Then, cut pork tenderloin in 1/2 inch thick slices and set aside. (These are your medallions, I formed mine with my hands to make a circular shape).
Grind pistachios in a food processor. Then add in breadcrumbs, zest, garlic, and rosemary and pulse until combined well. Set aside in a bowl.
Crack eggs in a medium bowl and whisk. Place flour (with the salt and pepper added) in a medium-large bowl. Line up your 3 bowls: egg wash, flour, and breadcrumb mixture.
Dip pork tenderloin slices in the egg wash, then in the flour, back in the egg and then in the breadcrumbs. Set on a plate.
Heat the canola oil in a frying pan until sizzling hot. The smoke point is 400 degrees for canola oil! Cook each medallion on each side for ~2 minutes, being sure not to burn the pistachio crust. You may need to work the pork in batches.
Place medallions on the prepared baking sheet and bake in oven for 8-10 minutes, or until fully cooked inside. Enjoy with your favorite side dishes!