Salt and pepper the meat thoroughly. 

Oil a cast iron casserole pot.

Place it in a preheated oven. 

Ten minutes later, after it is properly heated remove it and put the meat in it without adding any kind of liquid. 

Adjust the oven tempertature at  220-230 degrees. An hour and a half later, turn the meat over and bake for about half an hour more without opening the oven or the lid of the casserole pot. Even if it sticks a bit, it doesn't matter. It is better because all the extra fat will be gone. If the skin is not all that crunchy, bake for 10΄ more with the lid off. 

Even if it is overcooked in the iron cast casserole pot, it doesn't matter. 

Serve with potato purée and vegetables.