1. Preheat oven to 350 degrees F (175 degrees C). Lightly grease a cookie sheet.
2. Clean mushrooms and remove stems. Chop enough stem to yield one cup. Use a pastry brush to brush the caps with vegetable oil.
3. In a skillet, melt 2 tablespoons butter or margarine. Add chopped stems and onion to the hot butter. Saute the mixture for 4 minutes, remove it from the heat and let cool.
4. In a large mixing bowl, combine the mushroom-onion mixture, crabmeat, cream cheese, egg, 1 cup bread crumbs, parsley, pine nuts, salt, and pepper. Spoon the mixture into the mushroom caps. Arrange the caps on the prepared cookie sheet.
5. In a small skillet, melt the remaining butter and add the remaining bread crumbs to the melted butter. Once the bread crumbs are coated lightly sprinkle them over the mushroom caps.
6. Bake for 15 minutes.