Preheat your oven to 425°F (220°C) and prepare the cauliflower by trimming leaves and cutting into florets.

Spread florets on a baking sheet, drizzle with olive oil, and season with salt and pepper. Roast for about 45 minutes, turning halfway.

In a Dutch oven, heat olive oil over medium heat. Sauté onion for about 7 minutes until translucent.

Add garlic, cumin, paprika, sumac, and turmeric. Cook for about 1 minute until fragrant.

Stir in three-quarters of the roasted cauliflower.

Pour in vegetable broth and water, bring to a boil, then reduce heat and simmer for 5-7 minutes.

Blend the soup until smooth, leaving some texture if desired.

Return to low heat, add milk, and remaining cauliflower. Adjust seasoning.

Stir in lemon juice and dill just before serving.