Polenta Canapés with Chestnut Mushrooms

Rinse the lemon in hot water, pat dry, zest the lemon and squeeze the juice. Trim the mushrooms, cut into slices and sauté in hot oil for about 2 - 3 minutes. Season with salt and pepper and sprinkle with lemon juice. Heat a pan with a small amount of butter. Cut out small circles from the polenta and fry until golden brown on both sides. To serve, place the polenta slices on a serving dish, top with mushrooms and garnish with lemon zest and Parmesan.