Heat 1 tablespoon of olive oil in a large saucepan over medium heat. Add the chopped onion and sauté for about 5 minutes, stirring occasionally, until translucent and fragrant.

Stir in the minced garlic, cooking for another minute until fragrant, then add the trimmed and chopped asparagus pieces. Sauté for approximately 5 minutes, stirring frequently.

Pour in 4 cups of vegetable broth, increase heat to bring to a gentle boil. Reduce heat to low and let it simmer for about 15 minutes, or until fork-tender.

Remove the saucepan from heat and let it cool for a few minutes. Blend the soup in batches until smooth. An immersion blender can also be used.

Return the blended soup to the saucepan, stir in 1 cup of heavy cream, and season with salt, pepper, and lemon juice. Heat over low for about 5 minutes.

Adjust consistency with more broth or water if too thick. Taste and adjust seasoning if necessary. Serve warm.