Cooking a lean roast like pork tenderloin in a slow cooker is tricky because it can quickly turn overcooked and dry. We discovered that nestling two tenderloins side by side, alternating the narrow and thicker ends, helped to insulate the meat and prevented it from overcooking.
Once we had the method in hand, we developed the flavor, coating the pork with a teriyaki glaze made with equal parts sugar and soy sauce and seasoned with fresh ginger, garlic, and mirin.
To ensure a properly clingy glaze, we simply thickened the sauce with some cornstarch before applying it to the pork, and then we ran the tenderloins under the broiler before serving.
To prevent the pork from overcooking under the broiler, we removed it from the slow cooker just shy of 145 F. You will need an oval slow cooker for this recipe. Because they are cooked gently and not browned, the tenderloins will be rosy throughout. Check the tenderloins' temperature after 1 hour of cooking and continue to monitor until they register 145 F.
TERIYAKI PORK TENDERLOIN
Start to finish: 1 to 2 hours on low.
Slow cooker size: 4 to 7 quarts.
1/3 cup soy sauce
1/3 cup sugar
2 tablespoons mirin
1/2 teaspoon grated fresh ginger
1 garlic clove, minced
2 (12- to 16-ounce) pork tenderloins, trimmed
1 1/2 teaspoons cornstarch
1 tablespoon water
2 scallions, sliced thin
1 teaspoon sesame seeds, toasted
Combine soy sauce, sugar, mirin, ginger, and garlic in slow cooker. Nestle tenderloins into slow cooker, side by side, alternating thicker end to thinner end. Cover and cook until pork registers 145 F, 1 to 2 hours on low.
Adjust oven rack 6 inches from broiler element and heat broiler. Transfer tenderloins to aluminum foil-lined rimmed baking sheet. Transfer cooking liquid to small saucepan and bring to simmer over medium heat. Whisk cornstarch and water together in bowl, then whisk into cooking liquid and simmer until thickened, 3 to 5 minutes.
Liberally brush tenderloins with glaze and broil until spotty brown on top, about 5 minutes. Transfer tenderloins to carving board, tent loosely with foil, and let rest for 5 minutes. Slice tenderloins 1/4 inch thick, then transfer to serving dish. Drizzle with remaining glaze and sprinkle with scallions and sesame seeds. Serve.