I recently made pastrami from corned beef. Soaked it overnight in water and pickling spice, then rubbed it with fresh coarsely ground black pepper, coriander powder, mustard powder, brown sugar, paprika, garlic powder and onion powder. Smoked it at 225 until the IT hit 195. I then put it in the fridge until totally cooled, and placed in a steamer for an hour. It turned out tender and delicious. I believe the key to getting restaurant quality pastrami is cooling and steaming just prior to serving.