Preheat oven to 200 degrees C. Grease a baking dish with 50g of melted butter.
Remove stems from mushrooms. Set aside caps. Finely dice the stems.
Melt 2 tablespoons butter in a medium saucepan over medium heat. Stir in the chopped stems and spring onions and cook until soft, about 3 minutes. Remove saucepan from heat. Stir in lemon juice, crab meat, soft breadcrumbs, egg, dill and 30g cheese. Thoroughly blend the mixture.
Place mushroom caps in the buttered baking dish then stir until caps are coated with the butter. Arrange caps cavity side up then stuff cavities generously with the spring onion and crab meat mixture. Top with remaining cheese. Pour wine into the pan around the mushrooms.
Bake uncovered in the preheated oven 15 to 20 minutes, until cheese is melted and lightly browned. Serve warm.