How to Make It
Season the pork cutlets with salt and pepper. Put the flour, egg and panko into 3 separate shallow bowls. Dust the cutlets with the flour, then dip them into the egg and coat with the panko, pressing lightly to help the crumbs adhere.
In a large skillet, heat 1/4 inch of oil until shimmering. Fry the cutlets 2 at a time over high heat, turning once, until golden and crisp, about 3 minutes. Transfer to paper towels to drain.
Lightly butter the bread and top with the fried pork cutlets. Spoon the tonkatsu sauce on top of the cutlets and close the sandwiches. Cut into thirds and serve with dill pickles.