Mix all of the marinade ingredients together in a bowl until well combined. Pour into a plastic zip top bag, and add in the flank steak. Cut into two large sections if it is too large to fit into the bag. Remove excess air and seal the bag, ensuring the marinade coats the meat. Refrigerate overnight if possible, or for at least 2 hours.
To Cook –
Preheat oven to 425 degrees. Mix herbs, olive oil, and salt and pepper into a bowl. Toss the potatoes in the mixture. Place them on one half of the baking sheet. Toss the carrots and then the beans in any remaining oil and place them onto the baking sheet.
Bake vegetables for 15 minutes.
While baking, heat a skillet over medium high heat and drizzle lightly with olive oil. Sear steak for 3 minutes on each side. Place on top of the vegetables in the oven, and bake for an additional 10 minutes (for medium rare). Cook longer if you prefer a more done steak.
Allow the sheet pan to rest for 5-6 minutes prior to slicing the steak and serving.