- Place a medium-sized stock pot over medium-high heat. Add 1 tablespoon of olive oil to the preheated pan. Add onion and garlic to the pan and sauté until translucent. Add broccoli, vegetable broth and milk to the pan. Reduce heat and bring to a simmer. Cook ingredients until the broccoli is just crisp-tender.
- Add broccoli mixture to a blender with a tight fitting lid. Make sure not to fill the blender more than half full at a time. Add the avocado and spinach to the blender as well. Carefully pulse the ingredients until smooth and creamy. Taste soup and adjust seasoning with salt and pepper. Return soup to pot and heat back up to serving temperature. Garnish soup with croutons and Parmesan cheese.