Preheat the oven to 400 degrees Fahrenheit (200 degrees Celsius).

In a large baking dish, combine the cauliflower florets, quartered shallots, and garlic cloves.

Drizzle the olive oil over the cauliflower, shallots, and garlic. Sprinkle the salt, pepper, oregano, smoked paprika, and cumin evenly over the vegetables. Toss everything together to coat the vegetables evenly with the seasonings and oil.

Roast the mixture in the preheated oven for 20-25 minutes or until the cauliflower florets are tender and start to turn golden brown.

Once the roasted vegetables are done, transfer them to a medium-sized saucepan.

Add the bone broth in the same saucepan with the roasted vegetables over medium heat. Bring it to a simmer.

Use an immersion blender to puree the mixture until smooth. A regular blender can also be used, but be sure to allow the soup to cool slightly before blending, and blend in batches if necessary.

After blending, return the soup to the saucepan over low heat.

Stir in the 1/4 cup of heavy cream and continue to simmer the soup for a few more minutes until it's heated through and has reached the desired consistency.

Taste and adjust the seasoning if needed, by adding more salt or pepper to taste.

Serve the roasted cauliflower soup hot, garnished with a drizzle of heavy cream, croutons, and a sprinkle of za’atar seasoning.