Start by preparing 4 pieces of string, all the same length.
Next, place the pork loin in the center of the strings.
Place a wooden spoon over the meat, tie everything with the strings and set aside.
In a large pot, add the black peppercorns, the salt, the bay leaves and the onion peels.
Add the meat we prepared, resting the spoon on the sides of the pot, the water and let it cook for 40 minutes.
After this time has passed, brush fifty grams of melted unsalted butter all over the meat.
Add the pinches of salt, the garlic powder, the sweet paprika and using your hands, rub the spices all over the meat.
Then, wrap the meat in a sheet of aluminum foil and transfer it to a baking tray.
Take it to a preheated oven at 180° C (350° F) and bake for 15 minutes.
After this time has passed, remove the aluminum foil, place it back in the oven and let it roast until golden brown.
Serve.