In a large soup pot, melt the butter over medium heat. Add the chopped onion and garlic, and sauté until softened, about 5 minutes.

Add the asparagus and potato to the pot, stirring to combine.

Pour in the vegetable broth and bring to a boil. Reduce heat and simmer until the vegetables are tender, about 15-20 minutes.

Using an immersion blender or a regular blender, puree the soup until smooth.

Stir in the heavy cream, salt, black pepper, and lemon juice. Heat through and adjust seasoning if necessary.

Ladle the soup into bowls and serve hot, garnished with additional asparagus tips or a drizzle of cream if desired.