1. Center a rack in the oven and heat to 450 degrees. Arrange pork fat-side up on a cutting board with short end facing you. Holding a knife so it is parallel to the cutting board and 1/2" from the bottom of the pork, make a lengthwise cut into center of the loin, slicing and pulling back the meat with your free hand and unfolding it like a roll of paper towels. Place a piece of plastic wrap over the flattened meat and pound with a meat mallet until it is an even thickness (about 1/2"); uncover and season with salt and pepper.
2. Melt 2 tablespoons oil in a large nonstick skillet over medium-high heat. Add sweet potatoes, garlic, 1 teaspoon salt, and 1/2 teaspoon pepper and cook, stirring frequently, until potatoes are just softened, 6 to 8 minutes. Remove from heat and stir in 2 tablespoons mustard, breadcrumbs, sage, and 1 teaspoon paprika.
3. Leaving a 1" border all around, spread sweet potato mixture evenly over pork. Roll tightly into a cylinder and tie with butcher's twine in 1" sections. Place pork fat-side up on a rimmed baking sheet fitted with a wire rack.
4. Stir together remaining 1 tablespoon oil, remaining 1 tablespoon mustard, 2 teaspoons salt, remaining 1 teaspoon paprika, and 1/2 teaspoon pepper and rub all over pork. Roast until golden brown, 25 to 30 minutes. Reduce oven temperature to 375 degrees and continue to roast until center of pork registers 140 degrees, 30 to 40 more minutes. Transfer to a cutting board, tent loosely with foil, and let rest 20 minutes before slicing.
Source: Hannaford fresh Magazine, November - December 2016