Start by adding olive oil, balsamic vinegar, soy sauce, minced garlic, lemon juice, brown sugar, Dijon mustard, and red pepper flakes into a medium bowl. Whisk these ingredients thoroughly until the mixture is smooth and glossy. The balsamic vinegar acts as the star, bringing a tangy and slightly sweet depth, while the olive oil balances it with richness. Dijon mustard helps emulsify everything into a velvety consistency.

Place your chosen steak cut into a zip-top bag or a shallow dish. Pour the marinade over the steak, ensuring every inch is coated. Seal the bag or cover the dish tightly with plastic wrap. Pop it into the fridge and allow the steak to marinate for at least four hours. Marinating overnight works even better if you have the time, as it lets the meat soak up every bit of flavor.

Once marinated, take the steak out of the fridge and allow it to come to room temperature for about 20 minutes. Heat your grill or skillet on high until it’s scorching hot. Lay the steak down gently and cook for about 4-5 minutes per side for medium-rare, flipping once with tongs. This quick sear locks in the juices and gives the steak a beautiful crust.

After removing the steak from heat, cover it loosely with foil and allow it to rest for 5-10 minutes. This step is crucial for the juices to redistribute throughout the meat, making every bite juicy and tender. Slice the steak against the grain to make it easier to chew and serve with the remaining juices from the plate.