PREP: Remove flank steak from packaging and pat dry with paper towels. Place in a large resealable bag.
MARINADE: In a bowl, combine the olive oil, minced garlic, red wine vinegar, honey, soy sauce, pepper, and 1 tablespoon coarsely chopped Italian parsley. Whisk together and pour over the flank steak. Seal and place in the fridge for at least 1 hour and preferably 4-6 hours. Flip the steak in the bag halfway through the marinating time.
CHIMICHURRI SAUCE: I like to make this the same time I'm marinating the meat, because it gets more flavorful as it sits. In a large mason jar, add the finely chopped garlic cloves (2-3 cloves if sensitive to garlic, or 4 cloves for garlic lover!), red wine vinegar and freshly squeezed lime juice. Stir and set aside. Finely chop a bunch of parsley to get a full 1/2 cup gently packed (you should use most, if not all of a good sized bunch; some stems are fine -- I just remove the bulk of large stems and then chop the rest). Chop the cilantro and measure to get a lightly packed 1/2 cup. Add the parsley and cilantro to the mason jar along with the olive oil, dried oregano, red pepper flakes, and honey. Season to taste with salt and pepper (I use 1/2 teaspoon salt and 1/4 teaspoon pepper). Stir thoroughly. Cover and refrigerate while the meat marinates.
GRILL PREP: Preheat the grill to 450 degrees F. Once heated, clean the grill grates with a wire brush. Liberally oil the grill (I do this by drenching a paper towel in canola or vegetable oil and, holding tongs, rubbing the paper towel over the grill). This will ensure the meat doesn't stick to the grates and gets a great char (char = flavor!)
QUICK SPICES: Stir together 1 teaspoon salt, 1/2 teaspoon ground cumin, 1/2 teaspoon ground coriander seed, and 1/4 teaspoon black pepper.
STEAK: Remove from marinade and discard remaining marinade. Sprinkle half the rub on top of the steak. Place on fully heated grill (rub-side down) and quickly sprinkle the rub on top. Close grill lid. Cook for 4-5 minutes per side, or until the internal temperature is 130-135 degrees F for medium rare or 145 degrees for medium. (I use a meat thermometer here. My grill takes exactly 4 minutes per side at 450 degrees F.) Remove the steak from the grill to a cutting board. Tent with foil and allow to rest for 10 minutes. Once the steak has rested, slice it very thinly against the grain (See Note 1). Serve with chimichurri herb sauce.