Pork Spring Rolls

Marinate the pork: Combine 1 tablespoon soy sauce, brown sugar, and pepper in a large dish. Add the pork tenderloin, turn to coat, and let sit 15 minutes.

Make the sauce: Preheat oven to 400 degrees F. Stir together the plum sauce, crystallized ginger, remaining soy sauce, and mustard in a small bowl and set aside.

Cook the pork: Heat the vegetable oil over medium-high heat in a large, ovenproof skillet. Remove meat from marinade and brown on all sides. Transfer to the oven and roast until an internal temperature of 155 degrees F is reached -- 15 to 20 minutes. Place the pork loin on a cutting board, let sit 10 minutes, slice into 1/2-inch-thick strips, and set aside.

Assemble the spring rolls: Place the spring-roll wrappers in a large bowl and immerse in warm water. Let sit until softened -- about 3 minutes. Remove one wrapper from the water, place on a clean surface, and blot excess water with a paper towel. Place two pieces of pork, about 1 teaspoon of sauce, 3 cucumber pieces, and 3 onion pieces in the center of the wrapper toward the top and roll toward you to create spring roll. Repeat with remaining ingredients. Serve immediately or cover with a damp paper towel and refrigerate.