Materials and Supplies
Pellet grill
Wood pellets (cherry, post oak, competition, mesquite)
Smoke cage
Cherry wood chunks (4 pounds)
Raised grill racks
Foil tray (17 1/8" x 12 5/8" x 2 27/32"), filled with water
Butcher paper
Heavy duty foil (8.33 yard x 18")

Step 1
Start at 8 am the day before you want to serve the brisket.  Trim brisket, leaving a ¼” fat cap (see video link below)

Step 2
Place white fat in a slow cooker and cook on low while the brisket smokes.  You will use the rendered beef tallow during the wrap step.  Save any excess tallow and refrigerate.

Step 3
Rub yellow mustard on brisket and season liberally with salt and pepper, starting with the bottom, then sides and top

Step 4
Rest brisket at room temperature for 1 hour so salt and pepper adhere

Step 5
Meanwhile, place raised grill racks in smoker with water-filled foil tray beneath the racks. Preheat smoker to 225 F.  This foil tray acts as a heat sink to reduce hot spots and ensure more even cooking.

Step 6
Working outside the smoker, add a few of the smaller cherry wood chunks to the smoke cage and light using tumbleweed fire starters or a propane torch.  Burn the wood until it turns black and grey with orange flames, then place the smoke cage inside the smoker on the bottom rack on the side opposite of the smoker’s thermal sensor.

Step 7
Place seasoned brisket on upper rack of 225 F smoker, fat side up

Step 8
Smoke brisket at 225 F for 8 hours, adding cherry wood chunks every 30 minutes or so to generate flavorful smoke during this step

Step 9
After the 8-hour smoke step, remove smoke cage from smoker and set aside

Step 10
Wrap the corners of the flat and point with foil to prevent overcooking

Step 11
Increase smoker temperature to 300-325 F and smoke brisket until internal temperature reaches 190 F.  This can take 4-8 hours, or more, depending on the size of the brisket.

Step 12
Lay out butcher paper and drizzle ¼ cup tallow on the area where the brisket will be placed

Step 13
Remove brisket from smoker and place on tallow-coated butcher paper

Step 14
Drizzle another ¼ cup tallow directly on top of brisket, then wrap brisket tightly

Step 15
Remove foil tray from smoker, drain water, then place wrapped brisket inside tray

Step 16
Add ½ cup water to foil tray and tightly cover tray with heavy duty foil

Step 17
Place tray inside a pre-heated 150 F oven. I use the Hold Warm setting on my oven

Step 18
Allow brisket to rest in the oven at 150 F 12-18 hours until it is time to serve

Step 19
Unwrap brisket, cut into ¼ inch slices and serve immediately

Notes:
Video for how to trim a brisket is here. 
This recipe was inspired by the following Smoke Trails BBQ video: https://www.youtube.com/watch?v=H209v2JG23k