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- Preheat oven to 350°F. Line a rimmed baking sheet with foil and arrange an ovenproof rack over top. Mist rack with cooking spray; set aside.
- In a small bowl, whisk together 2 tbsp oil, vinegar and soy sauce; brush all over mushrooms. Let stand for 10 minutes.
- Meanwhile, in a food processor, pulse bread, Parmesan, zest, thyme, garlic powder and pepper until finely ground. Spread on a plate. In a shallow bowl, whisk egg with milk. Dip mushrooms in egg mixture, letting excess drip into bowl. Dredge in bread mixture, turning to coat. Arrange, stem side down, on rack. Drizzle with remaining 1 tbsp oil. Bake until tender and golden, about 40 minutes.
- Build sandwiches: Arrange half of mushrooms stemmed side up. Divide sauce, provolone and greens over each. Sandwich with remaining portobellos. Cut sandwiches in half.
- Serving Size 1 sandwich
- Calories 374
- Carbohydrate Content 25 g
- Cholesterol Content 74 mg
- Fat Content 23 g
- Fiber Content 5 g
- Protein Content 19 g
- Saturated Fat Content 8 g
- Sodium Content 812 mg
- Sugar Content 9 g
- Monounsaturated Fat Content 0 g
- Polyunsaturated Fat Content 2 g