Pastrami is nothing more than corned beef with a spicy, peppery bark.
First thing you need to decide is if you want to cure your own brisket, or buy one that is ready to go. You can typically find great deals on corned beef flats around St. Patrick’s Day in the meat case. But if you want to make your own, follow this recipe:
Start with a 4-5# beef brisket flat. Make a brine of 1 gallon of water, 2/3C kosher salt, 1t pink salt (Prague powder), 1 onion and 8 cloves of garlic. Dissolve the salt completely, then add in the onion and garlic. Place the brisket in a large resealable plastic bag and cover completely with brine. Refrigerate for 6-7 days, flipping the bag every day to keep things even.
If you buy a corned beef brisket that is already cured, just jump ahead to the next step.
For the pastrami rub, mix together 1/2C black coarsely cracked peppercorns, 1/2C coriander seeds, 2T mustard seeds, 1T brown sugar, and 1t ground ginger.
Rinse the brisket under water and pat dry. Place in a roasting pan and thickly apply the rub to all sides. Place in your smoker at 225F, fat side up. Cook for 8-10 hours until the the internal temperature reaches 170F. Wrap in butcher paper and continue to cook until it reaches 195F, about 3 additional hours.
When done, wrap and place in an insulated cooler for 2-4 hours. Slice across the grain and enjoy!