"Top Chef" Ryan Scott uses his chimichurri for double-duty: first, as a marinade, then as a zesty sauce on the side. Ryan says to be sure to use indirect heat when cooking the beef ribs, and not direct heat, so that the beef cooks slowly and has time for the fat to render and the beef to become tender.
For the chimichurri, in a medium bowl, add the cilantro, parsley, oregano, paprika, shallot, olive oil, and lemon juice and zest. Stir to combine, then let stand for about 20 minutes. (Sauce may be refrigerated at this point in an airtight container for up to 3 days; bring to room temperature before proceeding.) When ready to serve, season with salt and pepper, and stir in the vinegar.
For the ribs, reserve ½ cup of the chimichurri to serve on the side. Coat the ribs with the remaining ½ cup chimichurri and refrigerate at least 8 hours or overnight.
Prepare the grill for indirect heat and preheat to 225˚F.
Remove the ribs from the marinade and wipe off any excess. Season liberally with black pepper. Place on the cooking grates, bone-side down, and grill until they reach an internal temperature of 200˚F, about 3-4 hours, depending on the thickness of your ribs. Season the ribs lightly with salt and immediately baste with the beef stock, then grill for 5 minutes more. (Alternately, place ribs on a foil-lined baking sheet and roast in a preheated 250˚F oven until tender, about 4 hours. Finish ribs on a grill pan and cook for a couple minutes on each side while basting with the beef stock.)
Just before serving, season the remaining ½ cup chimichurri with vinegar and salt and pepper to taste. Serve alongside the ribs.