1-First Step: Preheat and prep your ingredients. Preheat the oven to 400 degrees F. While the oven heats, gather all ingredients and chop the beef fat trimmings into very small bits. Thin beef slices matter here, so if your roast beef is not already sliced thin, do that before you start cooking.

2-Second Step: Render the beef fat. Place the chopped beef fat trimmings into a pan over medium heat. Cook them until the pieces brown and release their fat. This part adds a deeper flavor to the gravy, which is one reason this Portillo Italian Beef Sandwich Copycat tastes so rich. Once browned, strain the fat and set it aside. You will use that strained fat in the gravy base for extra flavor. It sounds old-school, but it really makes the sandwich taste more like the real thing.

3-Third Step: Make the gravy. In a saucepan, combine the water, beef bouillon cubes, browned fat, browning and seasoning sauce, lemon juice, dried oregano, salt, black pepper, garlic powder, cayenne pepper, and pinch of MSG. Bring the mixture to a boil, then reduce the heat and simmer for 5 minutes. The gravy should be savory, lightly spiced, and very fragrant. You do not want it blazing hot for long periods, though. Keep it around 180 degrees F when possible so the beef stays tender instead of turning tough.

4-Fourth Step: Warm the rolls. Put the sandwich rolls in the oven for about 3 minutes. This gives them a little warmth and helps them hold up once the gravy goes on. A chewy roll works better than a soft one that falls apart right away.

5-Fifth Step: Heat the beef in the gravy. For each sandwich, add 1/4 pound of sliced beef to the warm gravy for 2 minutes. This is the magic move. The beef should get hot fast and soak up just enough flavor without overcooking. Use tongs to lift the beef from the gravy and place it directly on the warm roll. If you are making more than one sandwich, work in batches so the beef stays tender.

6-Sixth Step: Add toppings and serve. Top each sandwich with hot giardiniera or cooked sweet peppers, depending on whether you want a spicy or mild finish. Then spoon extra gravy over the beef. If you like a really saucy sandwich, add even more gravy on the side for dipping. That is it. You now have a fast, flavor-packed copycat sandwich that serves 4 people and fits into a busy schedule.