Preheat to 425 °.
Toss broccoli and cauliflower in a large bowl with olive oil, salt and black pepper.
Add garlic and crushed red pepper; toss well to thoroughly coat all pieces.
Coat a shallow baking pan (10x15x1-inch jelly roll pan) with cooking spray and arrange vegetables in single layer.
Roast 10 to 15 minutes or until slightly tender and beginning to brown but not burned.
Stir all vegetables once during cooking time.