In a blender, add the tomatillo halves, avocado, serrano peppers, onion, garlic, cilantro lime juice and salt.
Pulse until smooth. Taste, add more salt to taste and blend again.
Store in a food-safe, airtight container in the fridge for up to 1 week.
Notes
Remove seeds from the peppers if you don't want the spice. It's not extremely spicy, but they do bring a little bit of heat.Adapted from Atlanta Magazine