Combine the herbs and garlic in a food processor and finely chop.
Add the oil, vinegar, water, hot pepper flakes and salt and pepper and process until a thick sauce forms. The chimichurri should be highly seasoned.
Pour 1/2 of the chimichurri sauce over the meat and smush it around until well-coated. Marinate the meat for 30 minutes to 1 hour.
Set up the grill for direct grilling and preheat to high. Arrange the steak on the grate and grill until cooked to taste, about 2 minutes per side for medium-rare.
Transfer the churrasco steak to plates or a platter and serve the remaining chimichurri sauce on the side.
Black Bean and Corn Salad
12-16 sprigs fresh cilantro
Chop cilantro coarsely and place in medium bowl.
Rinse black beans and drain thoroughly and add to bowl.
Stir in remaining ingredients until well blended.
Cover and chill 15 minutes or more. Serve.