Philadelphia-Style Roast Pork Sandwiches

Preheat the oven to 325 degrees F (165 degrees C).

Make the pork: Remove the netting or strings from pork roast, keeping them intact to use again. Combine rosemary, parsley, garlic, 3 teaspoons oil, 1 tablespoon kosher salt, and 1 tablespoon pepper in a bowl. Slice open pork roast and spread it with herb mixture. Roll up pork and secure it with the netting or string. Rub remaining 1 teaspoon oil all over pork; season with more salt and pepper.

Place pork, fat-side up, in a roasting pan; pour in water.

Bake in the preheated oven, basting occasionally and adding more water if necessary, until an instant-read thermometer inserted into the meat reads at least 145 degrees F (63 degrees C), 1 1/2 to 2 hours. Remove from the oven and let rest for 10 to 15 minutes. Reserve pan juices in the roasting pan.

While the pork is resting, prepare fixings: Heat oil in a frying pan over medium heat. Stir in garlic and red pepper flakes; cook and stir until garlic is fragrant but not brown, about 3 minutes. Pour in chicken stock and bring to a boil. Add spinach, lemon juice, salt, and pepper. Reduce the heat to medium-low and cook, stirring occasionally, until spinach is wilted, 2 to 3 minutes.

Cut and remove the string from the roast. Cut pork into thin slices. Return sliced pork to the juices in the roasting pan.

Slice sandwich rolls. Sprinkle Manchego cheese over split rolls, add pork slices, and top with spinach.