Instructions

1. Preheat the oven to 350°F. Prep the onions by cutting off the top quarter of each. On the opposite end of each onion, cut off the root so that the onion can rest on a at surface. Do not peel. Place the onions in a large baking dish and add an inch of water. Bake until the onions are cooked through, checking periodically, 45 to 60 minutes. (Onions are done when they are soft and fragrant.) Remove from the oven and allow to cool. Peel the onions, then carefully remove the inner layers using a fork until only 2 layers remain, forming a cup. Reserve the insides of the onions for later use. 
2. Fill a large sauté pan with an inch of water and bring to a boil. Place the potatoes in the pan, cover, and steam for 15 to 20 minutes, or until tender, stirring occasionally and adding more water if needed to prevent sticking. Place the potatoes in a food processor with 1 teaspoon of olive oil and 1⁄2 teaspoon of rosemary leaves. Process until the potatoes are smooth. Set aside. 
3. For the mushroom filling, sauté the mushrooms and garlic in 1 teaspoon of olive oil until the mushrooms are tender and juicy, adding water as needed to prevent sticking. Transfer all but 1 cup of the sautéed mushrooms to a food processor with 1 teaspoon sea salt, 1 teaspoon poultry seasoning, and 2 cups of the reserved onion. Process until the mixture is roughly combined.
4. Fill the onion cups with alternating layers of mushroom filling and mashed potatoes. Top with sautéed mushrooms and pine nuts. Serve and enjoy!