- Heat oil and butter in a large nonstick pot over medium-high heat. 
- Add onion, garlic, celery, broccoli and saute until vegetables are partially softened and garlic is fragrant. This takes about 5 minutes. 
- Add broth, spinach, mustard, basil, oregano, thyme, parsley, salt, pepper and mix until combined.  
- Reduce heat to medium and continue cooking uncovered until all the veggies are softened.  
- Reduce heat to low and use a hand-held immersion blender to puree the soup until smooth and creamy. You can also puree in a blender in batches.  
- Mix in heavy cream slowly. I only added about ¾ cups because I added more as a topping, when serving. However, more can be added, per your preference. 
- Garnish with toppings of your choice and enjoy!