4 large green cabbage leaves, cut into fine strips
Bring a large pan of water to the boil.
Heat the oil in a deep frying pan and add the onion. Cook over a gentle heat, stirring, until soft but not browned. About 3 to 4 minutes.
Add the mushrooms and cook for a further 2 to 3 minutes, until the mushrooms are starting to brown.
Add the garlic and cook for a further minute, before adding the vermouth. Bring to a simmer and stir in the crème fraiche and tarragon. Once the sauce starts to bubble, season with salt and black pepper. Remove from the heat.
Meanwhile once the pan of water is boiling, add all the veg strips and blanch quickly for one minute, until soft. Drain and serve with the sauce.