Whisk together all of the ingredients for the chimichurri sauce in a small bowl and set aside.
Place the chicken legs in a medium bowl, add half of the chumichurri sauce and smother over chicken legs. Cover the bowl and refrigerate for at least several hours, or better yet, overnight and up to 24 hours.
Reserve the other half of chimichurri sauce for serving the chicken legs.
Preheat the grill to 300F at the grate level. Basically, the grill should not be very hot.
Remove chicken legs from the bowl and pat dry with paper towels. Some bits and pieces of herbs and chili pepper remaining on the skin are totally fine, but you want as much of the liquid and oil off as possible for better browning. Oil will also so drip can cause flare-ups. Discard any leftover chimichurri marinade.
Grill chicken legs over direct heat, flipping frequently, about every 3 minutes, until the chicken is cooked through and internal temperature has reached a minim of 165F.
Let the chicken rest for 3 minutes and serve with the reserved chimichurri sauce.
Acid and Alliums in Raw Sauce Construction
Red wine vinegar provides the primary structural acid in traditional Argentine chimichurri, acting as a sharp counterweight to heavy canola or vegetable oil. Unlike cooked tomato sauces, chimichurri relies entirely on finely chopped cilantro, fresh oregano, and green onions combined raw with minced garlic. Mincing the garlic finely ensures the pungent allium compounds distribute evenly through the emulsion rather than overpowering single bites. Letting this mixture rest before use allows the vinegar to mellow the raw bite of the green onions without dulling their crisp cellular structure. Reserve half of this sauce strictly for table service to maintain vibrant herbaceous notes that would otherwise degrade during cooking.
Managing Moderate Heat on the Grates
Maintaining a moderate grate temperature of 300 degrees Fahrenheit prevents the high oil content in the marinade from scorching the poultry skin prematurely. Patting the chicken legs thoroughly dry with paper towels before placing them over direct heat minimizes dangerous flare-ups caused by dripping oil. Frequent flipping every three minutes encourages even rendering of the subcutaneous fat beneath the skin. Insert an instant-read thermometer into the thickest part of the meat without touching bone to verify the internal temperature reaches 165 degrees Fahrenheit. Allow the cooked poultry to rest undisturbed for three minutes before serving to let internal juices redistribute fully.