Choose a lamb not bigger than 5 kg, as it needs to fit perfectly in the oven. Discard the head and soak the lamb in water to eliminate the specific smell and blood. Refrigerate. Change the water regularly. I guarantee that after this procedure the lamb will taste very good.

Season with salt and pepper, then refrigerate for 24 hours.

Simmer the lamb offals (heart, liver, lungs) in seasoned water. For stuffing use homemade pasta simmered in water with a little salt. Drain the pasta in a colander then rinse. Transfer to a bowl and mix with sautéed onion. Add the finely chopped lamb offals, salt, pepper and raw eggs ( it will keep the stuffing from falling apart after baking).

Stuff the lamb and sew it with a thick needle. Leave the ends of the thread a bit
longer, so it can easily be removed after cooking.

Grease the stuffed lamb with mayonnaise.

Cover the tray with baking paper and the meat with tin foil. Bake until done. Just before removing the lamb from the oven, uncover and let the meat brown.

Remove the threads before serving!