Cut the tenderloin into 1 1/2" thick pieces. Place each piece, cut side down, on a piece of plastic wrap. Sprinkle with a few drops of water and cover with another piece of plastic wrap. Pound out each cutlet to 1/4" thickness.
Liberally salt and pepper cutlets.
Make coating station - put flour in one shallow bowl, the bread crumbs in another bowl, and the three eggs in a third bowl. Beat eggs well.
Dip each cutlet into flour, dusting off excess. Then dip into egg, allowing excess to drain. Then dredge with bread crumbs, shaking off excess. Place on wire rack.
Continue with remaining cutlets. Place all on rack and allow to rest for at least 10 minutes.
While pork is cooking, make gravy.
Heat large cast iron skillet over medium high heat. Add oil. When oil is hot, add butter. Once it is done foaming, carefully place cutlets in the pan. Let cook, undisturbed, for 5 minutes.
Turn pork when the bottom is golden brown. Allow to cook through and brown on the opposite side. Serve immediately with gravy.