Place parsley and garlic scapes in the bowl of a food processor with the chopping blade in. Pulse until parsley is well chopped (but not smooth) and garlic scapes are minced.
While the processor is running gradually pour the olive oil and red wine vinegar through the opening in the top of the food processor and drop in the red pepper flakes. Process until thoroughly mixed but you can still see pieces of parsley.
Serve on the side of a grilled flank steak, chicken or white fish.
Notes
This can be made ahead and frozen for a couple of months before use.
If you want your steak to have extra flavor, brush some of the sauce on the steak 2 -3 hours before grilling and leave in the refrigerator to marinate. Serve the extra on the side.