Preheat oven to 200C/390F.Cut the broccoli into evenly sized florets and place into a mixing bowl.Add the oil, parmesan, salt and pepper and mix with your hands to ensure the broccoli is coated in the other ingredients.
I recommend using food safe disposable gloves to keep your hands clean.Line a roasting tray with parchment paper and evenly spread the broccoli over the tray.
Dab the butter over the broccoli.Roast in the oven for 20-25 minutes.
For best result remove the broccoli after 10 minutes to mix through and turn.
The broccoli is cooked when a knife is easily inserted into the thickest piece.Remove from the oven and serve.