Preheat your oven to 400 degrees f. and line a large sheet pan with parchment paper.
Place cauliflower florets onto your prepared sheet pan. Drizzle with oil and season with sea salt and pepper to your taste.
Roast for 25-30 min, or until cauliflower is tender and lightly browned/caramelized as shown in the video.
Once finished, transfer your roasted cauliflower to a large stockpot then add in the leek, broth, milk, garlic, and parmesan.
Gently simmer over medium-low heat for 20-30 minutes or so, then blend with an immersion blender until smooth.
Garnish with fresh parsley and serve hot.
Enjoy!