1Slice a medium to large size onion into thin rings and use half to layer the bottom of a tupperware for marinating.
2Slice outside skirt steaks in half to a manageable size.
3Generously season one side of the steak with salt, fresh ground pepper, oregano, and minced garlic.
4Squeeze lime juice over the seasoned side of the steak.
5Flip the seasoned steak slices onto the onion layer in the tupperware, seasoned side down.
6Repeat the seasoning process (salt, pepper, oregano, minced garlic, lime juice) on the other side of the steaks.
7Layer the remaining half of the sliced onions on top of the seasoned steaks.
8Cover the tupperware and refrigerate the steak to marinate for at least four hours.
9Wash and finely chop two bunches of fresh flat leaf parsley, removing the stems.
10Add two tablespoons of dried oregano, one tablespoon of chopped garlic, two tablespoons of red wine vinegar, one teaspoon of salt, one teaspoon of crushed red pepper, and half a cup of extra virgin olive oil to the chopped parsley.
11Mix the chimichurri ingredients well.
12If desired, blend the chimichurri with a stick blender to achieve a paste-like texture.
13Crank up the Blackstone griddle to a medium-high to high heat.
14Add a little oil to the hot griddle.
15Place the marinated skirt steaks on the griddle and let them sizzle for three to four minutes.
16Flip the steaks and cook for another three and a half to four minutes until they reach a medium-rare temperature (130-135 degrees Fahrenheit).
17Remove the steaks from the griddle.
18Cut the cooked skirt steak against the grain before serving with the homemade chimichurri.