Fry 500g sliced button mushrooms with 1 medium chopped brown onion for about 3 minutes on medium to high heat. Remove from the heat and add 250 ml (about 1 cup) of sour cream and mix through. Scoop into small ramekins and cover generously with grated cheddar cheese. Bake in a pre-heated oven at 180ºC for a few minutes and until bubbly and the cheese have melted. Garnish with freshly chopped parsley and serve with any kind of bread of toast.