Pebre is a slightly hot pesto-like sauce that makes a wonderful accompaniment to beef and pasta. In Chile, this fresh herb sauce is a staple on the table. You can use any thick-cut Grilling steak instead of Medallions if you like.
Combine parsley, cilantro, onion, dressing, hot pepper sauce, salt and pepper in blender or food processor. Blend until smooth. Divide in half. Place half in large sealable freezer bag. Refrigerate remaining half in covered bowl. Pierce medallions all over with fork, place in the bag with sauce. Seal and refrigerate for 1 hour (if using marinating medallions, marinate for 12 to 24 hours). Discard marinade from meat, pat medallions dry with paper towels.
Place on lightly greased grill over medium-high heat, cook in closed barbecue for 6 to 7 minutes per side for medium. Remove to clean platter, tent with foil and let stand for 5 minutes.
Meanwhile toss reserved pebre sauce with hot cooked pasta and chopped tomato. Serve with medallions