In a large bowl, combine the yogurt with the oil, lemon juice and spices. Season generously and mix well.
Add the diced mushrooms, and mix until they’re completely coated in the yogurt mixture. Leave to marinate for at least 20 minutes.
Heat the oven to 180°C (Gas Mark 4 / 350°F).
Lightly grease a baking tray, and spread the mushrooms out in a single layer. Roast for around 25 minutes, until the mushrooms are soft.
Serve warm with the fresh coriander.