Preheat your oven to 400 degrees f. and line a large sheet pan with parchment paper.
Place your cauliflower florets into a large bowl.
In a separate small bowl, whisk together all the remaining ingredients to create your ranch sauce.
Drizzle 2/3 of this ranch sauce over the cauliflower. Reserve 1/3 to use as a dipping sauce.
Thoroughly toss and stir to combine the cauliflower and coat it really well with the ranch sauce.
Allow the cauliflower to sit/marinate for 30 min or refrigerate (covered) overnight if possible for the best flavor.
Transfer your coated cauliflower to your prepared sheet pan and arrange it in a single layer without overlapping.
Roast for 35-40 minutes, flipping halfway, until browned on the edges.
Serve with the remaining ranch dip.