Heat the oven to 200 degrees Celsius.
Clean the mushrooms with a damp paper towel, wiping off all traces of soil.
Place mushrooms cap side down in a roasting dish and sprinkle over shallots, garlic and thyme.
Drizzle on the olive oil and season with salt.
Cover with foil and roast for 20 minutes, remove foil and cook for a further 5 minutes.
Serve hot with a few grinds of white or black pepper at the last minute.
