If using the optional dried mushrooms, cover them with boiling water and allow them to soak for 30 minutes before using. Reserving the soaking water, strain and set aside.

To prepare the vegetables, peel and thinly slice the medium onion and garlic. Peel the small pickling onions and trim the ends. Peel the baby carrots. Peel, quarter and core the parsnips and cut them into 1 in (25 mm) lengths.

Wipe the mushrooms clean and slice them in half. Break the cauliflower into small florets, and trim the brussels sprouts and cut them in half. Peel and slice the celeriac root into 2 in (50 mm) pieces that are about 1/2 in (15 mm) thick. Top and tail the beans, and shell or thaw the peas.

Melt 1 oz (25 g) of the butter in a large casserole dish with 1 tablespoon of the olive oil. Add the sliced medium onion, cover and cook for 2 - 3 minutes. Add the small onions and carrots and cook for 5 minutes. Add the garlic, bay leaf, a pinch of salt and a pinch of the fresh herbs, and cook for 3 minutes.

Add the celeriac, parsnips, another pinch of salt and of herbs, and cook for 5 minutes. Add the cauliflower florets, brussels sprouts, another pinch of salt and of herbs, and cook for 6-10 minutes, until slightly tender but crisp.

Meanwhile, heat the remaining butter and olive oil in a saucepan then add the fresh mushrooms. Saute the mushrooms over a medium-high heat for 3 minutes until the juices are released, then add the optional dried mushrooms and reserved juices, and the wine.

Cover the pan and simmer the mixture for 3 minutes before adding to the casserole.

Add the green beans and peas to the casserole and cook for a final 3 minutes. Remove the bay leaf, season with salt and black pepper to taste and add the remaining herbs. Serve immediately.