In the bowl of a food processor, combine the olive oil, sherry vinegar, lemon juice, parsley, basil, oregano, garlic and shallots. Pulse until well blended but do not puree. Add 1/4 teaspoon of the black pepper, 1/2 teaspoon of salt, and the crushed red pepper. Remove 1 cup of the chimichurri sauce from the processor and transfer to a non-reactive bowl, cover with plastic wrap and reserve at room temperature for up to 6 hours. (If cooking steak another day, refrigerate sauce and return to room temperature before serving.)

Season the steak with 1 teaspoon of the kosher salt on each side, as well as 1/4 teaspoon of the black pepper per side and place in a large, resealable plastic bag. Add the remaining chimichurri sauce from the processor. Seal bag and refrigerate the steak for at least 2 and up to 4 hours.

Once the steak has finished marinating, remove it from the refrigerator and let it come to room temperature for 30 minutes. Meanwhile, preheat a grill to medium heat. Brush the excess chimichurri sauce off the steak and set the steak over the hot grill. Cook for 6 minutes on the first side. Rotate the steak 45 degrees, and cook another 6 minutes. Turn the steak over and continue to cook until the steak is done, about 6 to 8 minutes for medium-rare. Once cooked, lay the steak on a clean cutting board, and allow it to rest for 5 to 7 minutes before slicing across the grain into 2-inch wide strips. Serve with crusty bread and the reserved chimichurri sauce.