Why This Recipe Works

There are many herbed roast pork tenderloin recipes, employing techniques such as crusting, marinating, and stuffing the pork with sundry combinations of herbs. In our recipe testing, we found that herb crusts were problematic because the herbs came close to combusting on the outside of the meat, while marinating the meat in an herb-infused oil was time-consuming and the herb payout was minimal. Stuffing the meat with an herb paste seemed like the most promising method. Instead of using olive oil in the herb paste, we chose butter, which tasters preferred for its rich flavor. Heartier, drier herbs, like sage and thyme, worked best in the paste in our recipe. To butterfly the tenderloins, we laid them flat on a cutting board and sliced down the middle of each. We left about 1/4 inch of meat intact, then opened the flaps like a book to spread the interior of each tenderloin with the herb paste. A rub applied to the exterior of the roasts caramelized in the oven to create a nicely browned crust.

Before You Begin

Pork tenderloins can vary greatly in weight; try to find 2 large roasts for this recipe. We prefer to remove the tough silver skin with a paring knife before butterflying.

Instructions

Adjust oven rack to middle position and heat oven to 450 degrees. Using fork, beat butter, mustard, lemon zest and juice, garlic, herbs, 1/4 teaspoon salt, and 1/4 teaspoon pepper in bowl until combined. Reserve 3 tablespoons butter mixture. Combine sugar, 1/4 teaspoon salt, and 1/4 teaspoon pepper in small bowl.

Pat tenderloins dry with paper towels and, following photos 1 to 4 below, butterfly tenderloins, spread interior evenly with herb-butter mixture, interlock tenderloins, and tie securely with kitchen twine at 1 1/2-inch intervals. Rub pork with oil and sprinkle sugar mixture evenly over exterior.

Roast meat on rimmed baking sheet until exterior is golden brown and meat registers 140 degrees, about 35 minutes, flipping pork halfway through cooking. Transfer to cutting board and brush top of pork with reserved herb-butter mixture. Tent with foil and let rest 10 minutes. Remove kitchen twine. Slice and serve.