Preheat your oven to 425 degrees f. and line 2 large baking sheets with parchment paper.
Place your prepared broccoli and cauliflower florets into a large bowl.
Drizzle with the oil, lemon juice and sprinkle with the seasonings. Toss very well to get all pieces evenly coated.
Arrange the florets into a single layer onto your prepared baking sheets.
Roast for 18-20 minutes, flipping halfway, until tender-crisp and lightly browned.
As soon as your broccoli and cauliflower is done to your liking, remove from the oven and sprinkle with the grated parmesan cheese.
Sprinkle with chopped parsley and enjoy!