Step 1

Preheat the oven to 400°F (200°C) and adjust the oven rack to the middle position. Line the bottom of a roasting pan, baking dish, or ovenproof skillet with foil.

Step 2

In a shallow bowl or a rimmed baking dish, stir together the panko or bread crumbs, rosemary, and garlic. Season generously with salt and pepper and stir in the oil.

Step 3

Coat the tenderloin with the mustard and then place the tenderloin in the panko or bread crumb mixture, turning to coat it all over and gently pressing the mixture so it adheres.

Step 4

Transfer the pork to the foil-lined pan, dish, or skillet and tuck the narrow end under the tenderloin so it doesn’t overcook. Roast the pork until almost no trace of pink remains and the meat registers at least 145°F [63°C] when a thermometer is inserted horizontally into the thickest part of the tenderloin, 20 to 35 minutes, depending on the exact size of your tenderloin.

Step 5

Transfer the pork to a cutting board and let it rest for 5 to 10 minutes.

Step 6

Cut into slices about 1/3 inch (8 mm) thick and serve immediately. (Although leftovers straight from the fridge aren't terrible!)