Scrub the mushrooms with a brush. Cut large mushrooms in half. Pour the flour into a bowl and stir in the beer. In another bowl, beat the egg whites with a pinch of salt until stiff. Spoon the egg whites into the flour mixture. Heat the sunflower oil in a frying pan to 180 degrees.

Dip the mushrooms into the flour mixture and then into the sunflower oil. Fry the mushrooms in small batches until golden brown and drain on paper towels. Meanwhile, in a food processor, blend the gorgonzola, mascarpone and milk into a smooth sauce. Finely chop the parsley. Sprinkle over the mushrooms.