Combine the olive oil, balsamic vinegar, garlic, golden syrup and sweet chilli sauce in a screw-top jar. Season with salt and pepper. Shake until well combined. (Alternatively, you can use a bowl and a whisk to combine these ingredients)
Place the mushrooms in a large ceramic bowl. Pour over the dressing and stir to coat. Cover and stand for 30 minutes to marinate (at room temperature is best, so don't place in the fridge).
Preheat oven to 220°C. Spoon the mushrooms and any remaining marinade into a greased baking dish or roasting pan. Roast for 20–25 minutes, turning twice during cooking. Roast until tender. Add some fetta (or goats cheese if your fancy), sprinkle with herbs and return to the oven for a minute or so, just so the cheese melts a little.
Serve, and drizzle over the marinade from the pan.
We have used basil and thyme for this recipe, but rosemary works well too - however it's best to add the rosemary at the beginning, so it roasts with the mushrooms and softens.