1 piece of beef tenderloin (2-1/2 pounds), fat and skin trimmed off
Marinade:
1/2 cup chopped Italian parsley or cilantro leaves
4 cloves garlic, minced
1/4 cup olive oil
1/4 cup dry sherry or red wine
3 tablespoons red wine vinegar
1 teaspoon freshly ground pepper
1 teaspoon salt
Cut the tenderloin lengthwise, with the grain, into 4 flat even strips. Place the strips between sheets of plastic wrap and gently pound with the side of a cleaver to form steaks 10 inches long and 1/2 inch thick.
Combine all of the marinade ingredients in a nonreactive dish or bowl. Add the beef. Cover and put in refrigerator for 1 to 2 hours, turning occasionally.
Preheat barbecue grill to very hot or you can use the broiler with rack 3 inches from the heat.
Drain the beef and blot dry with paper towels. Grill or broil the beef for 1 minute per side for rare; 1-1/2 minutes to 2 minutes per side for medium; and 2 to 2-1/2 minutes per side for well done.
Serve the beef with Chimichurri.