Add all of the ingredients into a blender or food processor and blend until combined. Add extra water 1 tablespoon at a time if sauce needs to be thinned. Taste and add more salt if needed.
Roast the pistachios which helps bring out the nutty flavor for the sauce.
You can replace the fresh oregano with 1 teaspoon of dried oregano.
While store-bought bottles can be quite convenient, they lack in flavor compared to the real thing. It really isn’t that much extra work to freshly squeeze the lemon and you’ll notice a difference in flavor.
If you want more heat, keep the seeds from the jalapeño in the sauce.