Lamb marinated with herbs

Ingredients:

- lamb different parts approx. 2 kg)

- 500 g champignon mushrooms

- 50 g butter

- 100 ml dry white wine

- 2-3 tablespoons extravirgin olive oil

- a tablespoon mustard

- dried thyme

- eight cloves of garlic

- a few tarragon leaves

- two stalks green garlic

- salt

- pepper.