For the polenta:
For the creamed wild mushrooms:
Make the polenta first. Bring the water and Maldon salt to the boil in a heavy-bottomed pan. Pour in the maize flour in a steady stream, and stir it with a wooden spoon until it thickens. Let it cook slowly for at least 30 minutes, and keep stirring so that it doesn’t catch; it should be thick and fully cooked. Pour it into a terrine mould or other suitable lined container, and set it aside to cool completely before you start cooking the mushrooms.
Put the butter and oil in a sauté pan over a medium heat; add the shallots and cook them gently until they are opaque. Then add the mushrooms and cook for a couple of minutes until soft. Add the garlic and white wine and increase the heat to reduce the liquid by three-quarters. Lower the heat and add the cream; cook the mixture and reduce the liquid once more, until it has the consistency of a sauce. Season with milled pepper and Maldon salt and finish with the chopped parsley.
Remove the cold polenta from its tin, cut it into squares and sauté it in a little oil. Place a slice of polenta in the centre of a serving plate and spoon on the mushrooms. Decorate the dish with sprigs of parsley, lightly sprinkle with Maldon salt flakes, and serve.
Tip: All the preparation for this dish can be done in advance. The mushroom mix can be reheated, but you must take care to cool it after making – and do not put the parsley in if you make it in advance. Leave that until you reheat it.