How to make it:
Remove the leaves off the sprigs. Finely mince them together. Place in a small serving bowl. Mince chives, yellow onion and garlic cloves; add to the herbs. When you mince the garlic, flatten the knife over the garlic and slide/smash the garlic into the cutting board. Doing this a few times will help create a paste while breaking down the garlic bits. Otherwise, feel free to use a mincing tool.

Zest two strokes of a lemon. You don't need much at all. Slice a "cheek" off the lemon and squeeze that juice into the herb mixture. You don't want much juice. Just enough to add a hint of brightness without tasting lemon itself.

Add splash of ACV and mix in olive oil until the sauce is wet. You don't want it too soupy, but you want it to have enough liquid for dipping - you want it to move. Add a pinch of salt and whisk it all together.

Set aside so the flavors marry, then cook your steaks. Drizzle the chimichurri over the sliced steak, or serve in small sauce cups for dipping.

Notes:

I used a mixture of flat-leaf and curly parsley. They are entirely unique in flavor, and will have notably different effects on any dish. I liked the blend of them together for this chimichurri.

Also, thyme and rosemary both are strong as fresh herbs. If the flavor is too intense, add more parsley and olive oil. 

Green onions and scallions are the same thing. They have a stronger flavor than chives. However, when thinly sliced, they are a good substitute if chives are not available.

Fresh herbs are best! Use whatever is available in your area.

You're going to love this. Enjoy!