If using chicken breasts, butterfly each breast and then place between two sheets of plastic wrap or parchment. If using pork, use whole cutlets or slice thicker chops into 1/4-inch cutlets. Pound each piece to an even 1/8–1/4-inch thickness using a meat mallet or heavy skillet. Trim any large bits of fat. Pat the cutlets dry with paper towels.

Season

Season both sides of each pounded cutlet with a light, even sprinkle of the salt and black pepper.

Set up dredging stations

Place the flour in a shallow dish. In a second shallow bowl, whisk the eggs with the milk until smooth. In a third shallow dish, combine the breadcrumbs and grated Parmesan (if using). Make sure the breadcrumb mixture is spread evenly so you can coat quickly.

Dredge

Working one piece at a time, lightly dredge a cutlet in flour, shaking off excess. Dip into the egg wash, letting excess drip off, then press into the breadcrumbs to fully coat. Place each coated cutlet on a wire rack or sheet pan; do not stack, to keep the crust dry and crisp.

Heat oil

In a large skillet (preferably cast iron or heavy-bottomed) add the vegetable oil and butter. Heat over medium-high until the oil reaches 350°F (if using a thermometer) or until a breadcrumb test sizzles immediately but the oil is not smoking. Adjust heat to maintain 325–350°F while frying.

Fry schnitzels

Carefully add 2–3 cutlets to the hot oil without crowding (work in batches). Fry until golden brown and crisp, about 2–3 minutes per side for thin cutlets. Use tongs to flip gently. If using a thermometer, cooked internal temperature should be 165°F for chicken or 145°F for pork followed by a 3-minute rest. Transfer finished schnitzels to a wire rack set over a sheet pan or to paper towels to drain.

Finish

If desired, pour off excess oil from the skillet between batches and add a little fresh butter to refresh the flavor before the next batch. Keep cooked schnitzels warm in a low oven (200°F) while you finish frying remaining pieces.

Serve

Sprinkle chopped parsley over the schnitzels and serve immediately with lemon wedges for squeezing. Traditional sides: potato salad, spaetzle, fries, or a simple green salad.