This can be an appetizer but VERY easily a main course
1/4 cup olive oil
2/3 cup sherry vinegar
3/4 cup fresh parsley, chopped
3 tablespoons fresh oregano, chopped
3 tablespoon fresh lemon juice
6 large cloves garlic, chopped
1 flank steak, 1 1/2 - 1 3/4 lb.
Salt & freshly ground pepper
You can make this in a bowl and add the meat to it but I made it in a bowl and marinated the meat in a large freezer zip lock bag. Either way, add the olive oil, vinegar, sherry, cilantro, oregano, lemon juice, garlic, and some salt in pepper into a bowl and stir it together.
Remove about 1/3 of the mixture and reserve for adding at the end.
Add the flank steak and the remaining mixture to a zip lock bag and refrigerate for several hours. About 3 hours would be great but 2 will do. Be sure to remove the steak from the refrigerator 20 -30 minutes before you start grilling. It's always better to grill meat at room temperature.
Grill the meat directly over the heat for about 6-7 minutes on each side or broil on broiler pan about 5 1/2 inches away from heat for 5 minutes per side. Or grill for about 5 minutes per side turning the meat over only once. If the meat looks like it is cooking too fast and is starting to burn, just move it over to a cooler spot on the grill. I brushed a little of the marinade on the steak before turning over.
Remove the steak from the grill/broiler pan, slice it across the grain into 1/4 inch wide pieces, plate it, and top it with the reserved Chimichurri sauce.
This is a meat that is more tender when it is rare to medium rare.