Chimichurri sauce hails from Uruguay and Argentina. It's commonly made with olive oil, red wine vinegar, garlic, red pepper flakes, finely chopped parsley, and dried or fresh oregano.
Uses- Vegetables – I like an assortment of red peppers, zucchini, asparagus, cherry tomatoes and Portobello mushrooms for grilling but you can use your favorite combination.
grilled chicken or steak. 
Ingredients:
3 cups flat-leaf parsley leaves (from about three bunches), very finely chopped
6 garlic cloves, very finely chopped
1½ tsp finely chopped fresh oregano leaves
¼ cup distilled white vinegar
2 tsp kosher salt
1 tsp freshly ground black pepper
¾ tsp dried red pepper flakes
1 bay leaf
¾ cup extra-virgin olive oil
Directions:
In an airtight container (medium size) combine the parsley, garlic, oregano, vinegar, salt, black pepper, bay leaf and red pepper flakes. Stir in the olive oil and refrigerate the sauce overnight.
It can be preserved in the fridge for 4 days.