Rinse asparagus and chop 1-2 inches off base to remove toughest part. Microwave or steam for 5-7 minutes to soften, then cut roughly into 1 inch pieces. Set aside the top ½ inch and chop finely for garnish.
Add oil to pot and sauté onions and garlic. Add salt and cook until onions are transparent, 5 minutes.
Add steamed asparagus pieces and broth. Bring to a boil and then remove from burner.
If you have a hand immersion blender, add avocado, lime juice and cumin to pot and blend directly in pot. If not, transfer onion and asparagus mixture to a free-standing blender and add the remaining ingredients. Puree until smooth. Salt and pepper to taste.
Top with a spoonful of Greek yogurt or sour cream, chopped cilantro, a drizzle of lime juice and finely chopped asparagus tops.