Preheat oven to 200ºC (180º fan-forced). Brush beef with 1 tablespoon oil and season. Place a rack in base of a roasting dish and place beef on rack. Add ½ a cup water to the base of dish. Cook for approximately 40 minutes for rare, 50 minutes for medium and 60 minutes for well done, covering with foil if overbrowning. Place beef on a plate, cover loosely with foil and rest for 20 minutes.
Meanwhile, place remaining oil, garlic, parsley, coriander, vinegar and chilli into a small food processor. Season and process until combined, adding a little extra oil if needed.
Heat microwave cauliflower and broccoli rice according to packet instructions. Place in a bowl with onions, season and top with parmesan.
Slice beef and serve with chimichurri, broccoli cauliflower rice and salad.
Whole beef fillet, scotch fillet or blade roast would also work well in this recipe.
Use 1 fresh birds eye chilli, finely chopped instead of dried chilli flakes for a hotter chimichurri.
Chimichurri will last in a sealed plastic container in the fridge for 2 to 3 days.