Bring the Big Green Egg up to 350 degrees F (180 degrees C) using lump charcoal. Any grill can be substituted here set up for 2 zone cooking.
Butterfly the Flank Steak (2.5 pound) by making a thin cut completely down the length of the steak (should open like a book and lay flat).
Season the top side of the flank steak Killer Hogs Steak & Chop Rub (1 tablespoon). Spread Cream Cheese (8 ounce) over the top side leaving 1-inch border from the edge.
Sauté the Mushroom (8 ounce) in Olive Oil (1 tablespoon) for 3 minutes and add Fresh Baby Spinach (2 cup). Cook the spinach just until wilted.
Layer the spinach-mushroom mixture on the cream cheese and top with Roasted Red Bell Pepper (1/4 cup).
Tightly roll the flank steak using your fingers to keep the stuffing inside. Leave it seam down on the cutting surface.
Use 16-inch pieces of butcher twine to tie the flank steak spacing each string out about 1 inch.
Season the outside with the remaining Killer Hogs The A.P. Rub (1 tablespoon).
Place flank steak on grill surface and sear on each side about 3-4 minutes per side.
Carefully raise the cooking grate and insert the plate setter in the Big Green Egg. If using another grill, move the flank steak to the indirect side. Grill should still be running at 350 degrees F (180 degrees C).
Insert Probe Thermometer into the middle of the flank steak and set alarm for 130 degrees F (50 degrees C).
When the steak is done, remove from grill and rest for 10-15 minutes.
Slice into 1-inch medallions to serve.