Preheat oven to 425° F.
Toss broccoli & cauliflower and 2 tablespoons of olive oil on rimmed baking sheet. Season with salt and pepper. Roast, tossing occasionally, until tender 15-20 minutes.
Meanwhile, pulse parsley, lemon juice and remaining 1 tablespoon of olive oil in blender/hand blender, until finely chopped. Season with salt and pepper. (Can be made 4 hours ahead).
Toss broccoli & cauliflower with lemon parsley mixture and top with lemon zest. Enjoy!