Chimichurri is an Argentinean sauce or condiment that is similar to pesto.  The basic version (which is the one I prefer) uses fresh parsley, oregano, garlic, oil and vinegar.  If you like it hot you can add a touch of chili pepper.  You can add variations to the sauce to your tastes and likes so the combinations are endless.  In Argentina folks use this both as a marinade or a sauce for grilled steak, but try it on fish, chicken or pasta.    
Ingredients:
- 1 cup firmly packed fresh flat-leaf parsley, thick stems trimmed
 - 3-4 garlic cloves
 - 2 tablespoon fresh oregano leaves (or 2 teaspoons dried oregano)
 - 1/2 cup olive oil
 - 2 tablespoons red or white wine vinegar
 - 1 teaspoon sea salt
 - 1/4 teaspoon freshly ground black pepper
 - 1/4 teaspoon red pepper flakes (optional)
 
Finely chop the parsley, fresh oregano and garlic (or use several pulses on your food processor). Place in a small bowl.
Stir in the olive oil, vinegar, salt, pepper and red pepper flakes. Adjust the seasonings to taste.
Serve immediately or refrigerate either as a sauce or accompany with a soft bread for dipping. If chilled, return to room temperature before serving. Can keep in the refrigerator for a day or two.
Serves 4.

