Hot Slow-Roasted Pork, Onion, and Mozzarella Sandwiches

PreparationFor pork: Chop garlic on work surface. Sprinkle with 1 1/2 teaspoons kosher salt and mince until paste forms. Transfer paste to small bowl; mix in parsley and next 7 ingredients. Using small sharp knife, make 20 evenly spaced 1-inch-long, 2-inch-deep slits in pork. Stuff seasoning mixture into slits. Sprinkle outside of pork with salt and pepper. Let stand 1 hour for seasonings to penetrate. Position rack in bottom third of oven and preheat to 325°F. Place rack in large roasting pan; place pork on rack. Roast until thermometer inserted into thickest part registers 170°F, about 4 1/2 hours. Let pork rest 30 minutes. Transfer to work surface. Maintain oven temperature; reserve roasting pan. Thickly slice pork off bone. Coarsely chop or tear slices and place in large baking dish; cover with foil. Pour juices from roasting pan into 4-cup measuring cup. Spoon off fat. If necessary, add enough water to degreased juices to measure 2 cups. Stir 2 tablespoons juices and cornstarch in small saucepan until cornstarch dissolves; whisk in remaining juices and vinegar. Whisk over medium heat until sauce boils and thickens, about 2 minutes. Season to taste with salt and pepper. For vegetables: Heat oil in heavy large skillet over medium-high heat. Add onions and all peppers; sauté until vegetables are tender and brown, stirring occasionally, about 30 minutes. Sprinkle with salt and pepper. Arrange roll bottoms on work surface; mound with warm pork and drizzle with sauce. Cover with cheese, vegetables, and roll tops. Serve warm. Do-ahead tip:The pork, sauce, and vegetables can be made one day ahead. Cover and refrigerate everything separately. Before serving, reheat pork, covered, in 350°F oven about 40 minutes; rewarm sauce and vegetables over medium heat.

PreparationFor pork: Chop garlic on work surface. Sprinkle with 1 1/2 teaspoons kosher salt and mince until paste forms. Transfer paste to small bowl; mix in parsley and next 7 ingredients. Using small sharp knife, make 20 evenly spaced 1-inch-long, 2-inch-deep slits in pork. Stuff seasoning mixture into slits. Sprinkle outside of pork with salt and pepper. Let stand 1 hour for seasonings to penetrate. Position rack in bottom third of oven and preheat to 325°F. Place rack in large roasting pan; place pork on rack. Roast until thermometer inserted into thickest part registers 170°F, about 4 1/2 hours. Let pork rest 30 minutes. Transfer to work surface. Maintain oven temperature; reserve roasting pan. Thickly slice pork off bone. Coarsely chop or tear slices and place in large baking dish; cover with foil. Pour juices from roasting pan into 4-cup measuring cup. Spoon off fat. If necessary, add enough water to degreased juices to measure 2 cups. Stir 2 tablespoons juices and cornstarch in small saucepan until cornstarch dissolves; whisk in remaining juices and vinegar. Whisk over medium heat until sauce boils and thickens, about 2 minutes. Season to taste with salt and pepper. For vegetables: Heat oil in heavy large skillet over medium-high heat. Add onions and all peppers; sauté until vegetables are tender and brown, stirring occasionally, about 30 minutes. Sprinkle with salt and pepper. Arrange roll bottoms on work surface; mound with warm pork and drizzle with sauce. Cover with cheese, vegetables, and roll tops. Serve warm. Do-ahead tip:The pork, sauce, and vegetables can be made one day ahead. Cover and refrigerate everything separately. Before serving, reheat pork, covered, in 350°F oven about 40 minutes; rewarm sauce and vegetables over medium heat.