Tenderize the meat: Start by tenderizing the flank steak with a meat tenderizer. Gently pound the steak with the tenderizer across the surface to help break down the fibers, which will make the steak more tender. This step also allows the marinade to penetrate more deeply into the meat, enhancing flavor and texture.
Prepare the marinade: In a mixing bowl, combine the soy sauce, minced garlic, salt, black pepper, paprika, olive oil, and vinegar. Stir well until all ingredients are thoroughly mixed.
Marinate the Steak: place the flank steak in a shallow dish or a resealable plastic bag. Pour the marinade over the steak, ensuring it’s evenly coated on both sides. If using a dish, cover it tightly with plastic wrap. Marinate the steak in the refrigerator for at least 4 hours, or ideally overnight for the best flavor and tenderness.
Preheat the broiler: when ready to cook, preheat your oven’s broiler on high and position the oven rack about 4-6 inches from the heat source. If you prefer using a grill pan, heat it over medium-high heat until very hot (you should be able to hear a slight sizzle when a few drops of water touch the pan).
Broil or grill the steak: Remove the steak from the marinade and let any excess drip off. Place the steak on a broiler pan or grill pan. Cook for about 5-7 minutes on each side for medium-rare (internal temperature should reach about 130°F or 54°C) or slightly longer for medium (135°F or 57°C). Avoid overcooking, as flank steak can become tough when cooked past medium.
Rest and slice the steak: Once the steak is cooked, transfer it to a cutting board and let it rest for 5-10 minutes. This step allows the juices to redistribute throughout the meat, ensuring each slice is juicy and flavorful. After resting, slice the steak thinly against the grain (the direction in which the muscle fibers run) for the most tender texture.