Preheat the oven to 375 degrees.
Combine 2 tablespoons of olive oil, 2 cloves of minced garlic, 1/2 teaspoon of dried basil, 1/4 teaspoon dried oregano, a pinch of crushed red pepper flakes, sea salt, and freshly cracked pepper together in a large zip lock bag.
Add the flank steak and seal the bag then squish the bag so the marinade is completely covering the flank steak evenly.
Set on the counter for 30 minutes to marinate.
While the steak is marinating, combine the grape tomatoes, garlic slivers, 1/4 teaspoon dried basil, 1/8 teaspoon dried oregano, a pinch of crushed red pepper flakes, sea salt, and freshly cracked pepper.
Drizzle with the last tablespoon of olive oil and the balsamic vinegar then toss to coat evenly.
Place the tomatoes into the oven to roast, gently stirring halfway through, for 20 minutes, or until tomatoes are ready to burst. Remove from the oven.
Heat a large cast iron skillet over medium-high heat.
Place the flank steak into the HOT pan and cook for 3-4 minutes on the first side, flip and cook for 2-3 minutes on the other side, for medium-rare, or until you reach your desired degree of doneness.
Transfer the beef to a cutting board and let the meat rest for 5-7 minutes before slicing and serving topped with the balsamic roasted tomatoes and their juices then sprinkle with fresh parsley and parmesan cheese. Serve immediately. Enjoy.