Heat olive oil in a large pot over medium heat and sauté chopped onion until softened, about 5 minutes.

Add minced garlic to the pot and cook for 1 minute until fragrant.

Add chopped asparagus and vegetable broth, bring to a boil, then reduce heat and simmer for 15-20 minutes until tender.

Puree the soup using an immersion blender until completely smooth.

Return the soup to the pot and stir in the heavy cream, Parmesan cheese, and butter until heated through.

Season with salt and black pepper to taste.

Ladle into bowls and garnish with fresh parsley before serving.