Cut the pork tenderloin into thick pieces about 1 to 1 1/4 inches (2.5–3 cm) thick.

Pound them with a rolling pin to half their thickness.

Here's the key point!

Left: before pounding
Right: after pounding.

Season with coarsely ground black pepper and salt.

Heat a small amount of oil (not listed in ingredients) in a pan over medium heat and cook the pork.

Serve with whole grain mustard on the side.