Place a jelly-roll pan in oven. Preheat oven to 450°F (leave pan in oven). Combine olive oil, miso, and garlic. Massage mixture evenly onto cauliflower florets. Remove pan from oven; coat pan with cooking spray. Add cauliflower to pan. Bake until crisp-tender, about 20 minutes, stirring after 10 minutes.
We love roasted cauliflower. First time I've tried it with miso. Very good and will definitely make again.