In a large pot, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes.

Stir in the minced garlic, diced carrots, and celery. Cook for another 5 minutes until the vegetables start to soften.

Add the zucchini, asparagus, and peas to the pot. Stir well to combine.

Pour in the vegetable broth and bring the mixture to a boil. Reduce heat and let it simmer for 15 minutes, or until all the vegetables are tender.

Using an immersion blender, carefully blend the soup until smooth. If you prefer a chunkier texture, blend only half of the soup and leave the rest as is.

Stir in the heavy cream, dried thyme, salt, and pepper. Heat through for another 5 minutes, but do not let it boil.

Remove from heat and add the fresh lemon juice. Taste and adjust seasoning if necessary.

Serve hot, garnished with chopped parsley.