Heat butter in a large soup pot over medium heat. Add onion and potato and sauté for 3-4 minutes.

Add vegetable broth and simmer for 15 minutes, or until potatoes are tender.

Add peas and simmer for 2 minutes. Add spinach and remove from heat. Stir until spinach wilts.

Transfer soup to a blender and puree until smooth. Add mint and cilantro and puree again.

Return soup to pot and heat. Add lemon juice and season with salt and pepper.

Stir in heavy cream. Serve hot or cold, garnished with olive oil and cherry tomatoes.