Chimichurri was originally developed in Argentina as a condiment to grilled meat (they eat a lot of meat down there).
The origin of the name is still in debate, but some in Argentina say it orginated after a military battle with the British. The British prisoners were demanding something to put on the food they were given. As the story goes, they mixed English, Spanish and a native dialect to make the phrase "che-mi-curry," roughly "give me condiment or give me curry." Some decades of corruption resulted in "chimichurri" and the words stuck, spreading through South America, Central America and the Caribbean.
The original Argentine recipe is made from finely chopping parsley, garlic and oregano and then mixing it with olive oil and white wine vinegar. It's traditionally a vibrant green sauce, but as it spread the recipe gained some ingredients here or shed some there. Depending on what ingredients you had nearby, the flavors of the different chimichurris vary wildly. Some recipes are deep red, made with tomatoes and bell peppers.
The type of chimichurri you preferred also depended on what you had on hand to serve it with. There was basically no red meat in the Caribbean, so this version was created to pair well with poultry and fish.
In addition to the original base ingredients, the Caribbean version includes mint and cilantro, giving it a brighter, lighter flavor that doesn't overpower more subtle flavors.
It’s one of those dual use sauces that works perfectly as a marinade or as dressing for finishing the dish. Prep some salmon or chicken breasts in the chimichurri then keep some on hand to drizzle over the food after it rests from the grill. It works great with flank steak, especially as a marinade.