Preheat oven to 400 degrees.
In a large mixing bowl, toss Brussels sprouts with cannabis oil, lemon juice, salt and pepper and toss to coat.
Place in a single layer in a baking dish or cast iron skillet and roast for about 10 minutes. Stir and roast for another 10 minutes. Stir and top with Parmesan and roast for another 10 to 15 minutes until sprouts are semi-tender. Sprinkle with additional lemon juice, if desired, and serve.