Preheat your oven to 400°F (200°C). Line a large rimmed baking sheet with parchment paper.

In a mixing bowl, toss the cauliflower florets with 2 tablespoons of olive oil, along with salt and freshly ground pepper until evenly coated.

Spread the cauliflower in a single layer on the prepared baking sheet and roast for 25-30 minutes until golden brown with crispy edges.

During the last 10 minutes of roasting, heat the remaining 1 tablespoon of olive oil in a large pot over medium heat.

Add the diced onion and cook for 5-6 minutes, until softened and translucent.

Add the minced garlic and cumin to the pot and cook for about 1 minute, stirring constantly until fragrant.

Once the cauliflower is roasted, add it to the pot along with the vegetable broth.

Bring the mixture to a boil, then reduce the heat to medium-low and let it simmer for 10 minutes.

Remove the pot from heat and using an immersion blender, blend the soup until it is completely smooth and creamy, about 2-3 minutes.

Stir in the fresh lemon juice and adjust seasoning with salt and pepper as needed.

If the soup is too thick, thin it with additional broth.