Crush the garlic then finely chopped the shallots and leeks together. Also finely chopped the mushrooms together.

Heat the butter in a large frying pan then add the chopped shallots and leeks. Fry gently for 7 minutes until softened.

Increase the heat then add the chestnut and shitakke mushrooms.

Cook for 10 minutes, stirring until the juices have evaporated and the mushrooms are tender

Stir in the mustard and the crème fraiche, cook for a further 2 minutes then stir in the tarragon.

Serve warm over French bread with some salad leaves and more tarragon to your taste.