For the brine: In a large stockpot, add half of the water, the brown sugar, kosher salt, curing salt, coriander seeds, mustard seeds, fennel seeds, juniper berries, chile flakes, bay leaves, cloves, cinnamon and star anise and bring to a boil. Then simmer for 30 minutes. Add the remaining water with some ice to chill the brine.
For the rub: Grind the peppercorns, coriander and juniper until crushed but still a little chunky. Add to a mixing bowl. Add the salt, brown sugar, chile flakes and granulated garlic and stir to combine.
For the pastrami: First, clean all the fat off the brisket including the "V" between the two muscles, then follow the fat between the two muscles and separate them making a flat and a cap.
Transfer the brine to a large hotel pan or roasting pan. Add the brisket and refrigerate at least 5 days and no more than 10 days. Make sure the brisket is stirred once a day to get an evenly brined brisket.
After a minimum of 5 days, prepare a smoker for 225 degrees F.
Remove the pastrami, rinse it and blot dry with paper towels. Thoroughly rub the brined brisket with the pastrami rub. Place in smoker and cook for 8 hours until the internal temperature reaches 210 degrees F on an instant-read thermometer.