In a blender, combine avocados, broth, lime juice, cilantro, onion, garlic, jalapeño (if using), cumin, and salt.
Blend on high until completely smooth, about 1-2 minutes.
Add Greek yogurt (or coconut milk) and blend again until creamy.
Transfer to a bowl and refrigerate for at least 1 hour.
Before serving, adjust seasoning with salt and lime juice if needed.
Garnish with diced avocado, cilantro, and a drizzle of olive oil.