Tofu and Walnut Stuffed Mushrooms

From SELF magazine. This is credited to Chef Nadine Barner, who supposedly has served these at Gwyneth Paltrow's parties.

• Ready In: 1 hr
• Serves: 12

Ingredients

• 1  medium onion, diced small
• 2  garlic cloves, peeled and finely chopped
• 1⁄4 cup olive oil, divided
• 14  ounces firm tofu, frozen and then defrosted (see note below)
• 1⁄2 teaspoon dried rosemary, crumbled
• 2  small tomatoes, finely chopped
• 1⁄3 cup ground walnuts
• 2  teaspoons  mellow miso (or more for stronger flavor)
• 1⁄2 teaspoon  balsamic vinegar
• 2  tablespoons tomato paste
• 12  large  fresh cremini mushrooms or 12  large white mushrooms, wiped clean, stems removed
• 1⁄4 cup  chopped green onion
•  salt and pepper

Directions

1. Freezing tofu changes texture to a more meaty substance that soaks up flavor. Freeze in plastic wrap, thaw and pat dry with paper towel to remove excess water.
2. Preheat oven to 350°F
3. In a large skillet, sauté onion and garlic in 2 tbsp oil, with a pinch of salt, until tender.
4. Crumble tofu over onion and sauté another 5 minutes.
5. Add rosemary and tomatoes and cook on low heat about 10 minutes or until mixture is fairly dry.
6. Add walnuts, miso, vinegar, tomato paste, and salt and pepper to taste.
7. Drizzle remaining 2 tbsp oil over mixture.
8. Place mushrooms in a baking dish and fill each with about 1 tbsp stuffing, using a spoon and pressing firmly to pack.
9. Bake 20 minutes.
10. Remove and top each with a sprinkle of green onion. Serve warm.