Wash and dice all the vegetables into small, uniform pieces.

Set aside the diced vegetables for later use.

In a large pot, heat the olive oil over medium heat.

Add the onions, carrots, and celery; sauté for about 5 minutes until softened.

Stir in the potatoes, broccoli, and zucchini, and cook for another 5 minutes.

Pour in the vegetable broth and bring to a boil.

Reduce heat and let it simmer for 20 minutes, or until all vegetables are tender.

Using a blender, carefully blend the soup until smooth. You may need to do this in batches.

Return the blended soup to the pot.

Stir in the heavy cream and season with salt, pepper, thyme, and garlic powder.

Heat through for an additional 5 minutes, then serve hot.