Preheat the oven to 200°C (400°F) and line a baking sheet with parchment paper.
Cut the cauliflower into florets about the size of a golf ball.
Place on the baking sheet and drizzle or brush with oil.
Bake for 15 minutes or until the cauliflower starts to brown. Toss from time to time.
Meanwhile prepare the chimichurri sauce by combining all ingredients in a blender or food processor.
Pulse until relatively smooth.
Add salt to taste.
Pour half of the sauce over the cauliflower and use a spoon to distribute the sauce well. Make sure to cover most of the vegetables in sauce.
Bake for another 10-15 minutes.
Remove from oven and serve. Pour more sauce over the cauliflower.