8 cups diced potatoes
2 teaspoons olive oil
½ teaspoon fresh rosemary leaves
8 cups chopped mushrooms
2 garlic cloves
1 teaspoon salt
1 teaspoon poultry seasoning
2 tablespoons pine nuts
Preheat oven to 350. Cut each end off all onions, do not peel. Place onions in a large baking dish and add an inch of water. Bake until ions are cooked through, about 40-60 minutes. Remove from oven and allow to cool. Peel the onions, then carefully remove the inner layer, leaving 2 layers.
Fill a large pan with an inch of water and bring to a boil. Add potatoes and cover for about 15-20 minutes. Place the cooked potatoes in a food processor with 1 teaspoon oil and ½ teaspoon rosemary leaves and process until smooth.
Saute mushrooms, garlic and 1 teaspoon olive oil until mushrooms are tender. Add water as needed to prevent sticking. Transfer all but 1 cup of mushrooms into a food processor with 1 teaspoon salt, 1 teaspoon poultry seasoning and 2 cups of the reserved onions and blend until mixture is roughly combined.
Fill the onion cups with alternating layers of mushrooms and potatoes. Top with sauted mushroom and pine nuts.