You need to "tri" this sandwich from Brooklyn

We just threw a huge New York Wine and Food Festival bash hosted by impossibly masculine celebrity chef Robert Irvine called Barbecue & the Blues. 16 NYC restaurants gave us their takes on BBQ, including Fletcher's Brooklyn Barbecue who slayed the crowd with their Brooklyn Dip. Because we know you totally dominate your kitchen/kitchenette, we snagged the recipe for you.Ingredients2.5 lbs Tri-Tip, peeled 2 tbsp coarse black pepper 4 tbsp fine sea salt1 tsp granulated garlic Olive oil 2 cups portobello mushroom, chopped 1 large Spanish onion, cut into strips4 cups beef broth 2 hearty hero bread loaves 1. Pre-heat a cast iron skillet, grill pan or charcoal grill (preferred) to high heat and pat dry the Tri-Tip with a clean towel or paper towels. Combine all the seasoning ingredients and coat the meat on all sides.2. Heat the beef broth over medium-high while you pre-heat the pan (or grill). Trim the ends of the hero bread and slice the loaves in half. Set aside while you finish the steaks.3. Using a teaspoon of olive oil per Tri-Tip, lightly coat the meat, then immediately place it onto the heat and sear it very well for about 3mins on all sides. When it is nicely charred, remove the meat to a platter, lightly tent with foil and let it rest for 5mins.4. In the same pan in which you cooked the steak (or in a skillet if you used a charcoal grill), add 2 tbsp more of olive oil and quickly sauté the mushrooms and onions together until the mushrooms begin to brown and have reduced in size and released all their moisture. Season with salt and pepper.5. Cut the meat as thinly as you possibly can against the grain, and lay the slices down on the bottom pieces of the hero bread. Layer the mushrooms and onions on top of the Tri-Tip. Dip the top of the hero bread in the warm beef broth and top the sandwiches.