Tri-Tip Sandwich
Remove the tri-tip from refrigerator 30 minutes before cooking. Set smoker to 225°F.
Smoke the tri-tip for about 1 hour, or until the internal temperature is 120°F for medium rare. Remove the steak from the grill and let rest. Heat a cast iron pan on high. Place the duck fat in the bottom of the cast iron, and sear the tri-tip for 3 to 4 minutes per side, until internal temperature is 130-135°F and a good crust has formed. Let rest, tented in foil, for at least 10 minutes before slicing very thin against the grain. Set aside.
Using a serrated knife, slice the flatbread in half lengthwise (if you can’t find flatbread, ciabatta is the next best option). Cover the base of the bread in grainy mustard and the top side in pepper jelly, spreading all the way to the edges. Place the freshly sliced avocado slices in a layer, covering the base of the bread, and sprinkle with
flake salt and pepper.
Cover the avocado with a handful of arugula, and top the arugula with a thick, double layer of the thinly sliced tri-tip. Place the tri-tip layers in opposite directions to make them easier to bite into and
to give your sandwich girth and height.
Spoon a liberal amount of chimichurri over the steak and cover with the top half of the flatbread.
Slice and serve.
Tri-Tip Marinade
Combine all the ingredients for the marinade in an extra-large plastic bag or bowl. Add the tri-tip and marinate in the refrigerator for 2-3 hours.
Chimichurri
Combine all ingredients and refrigerate until ready to use.