Preheat the oven to 400F.

Chop the butternut squash. Peel and dice the carrots. Peel and dice the sweet potatoes.

Put the squash, carrots, and sweet potatoes in a large bowl and toss with the olive oil, cumin, and 1 teaspoon black pepper.

Spread them out onto a baking sheet in a single layer and roast for 30 to 40 minutes, or until soft and yielding.

Transfer the roasted vegetables to a large saucepan over medium heat and add the vegetable broth.

Use an immersion (stick) blender to puree until smooth. (Alternatively, combine everything in a food processor and puree.) Add more broth if necessary, until you get a creamy soup consistency.

Add the za’atar, salt and pepper to taste, and stir well.

Serve hot with a sprinkling of za’atar, toasted sesame seeds, and yogurt if desired. Serve with flatbread.