Preheat oven to 350. Clean mushrooms with vegetable brush or wipe with damp cloth.
Heat oil in nonstick skillet over medium high heat. Saute chopped mushroom stems, onion, garlic and walnuts til onion is tender, about 4 to 5 minutes. Remove from heat. Stir in shredded wheat, Parmesan, herb seasoning and pepper to taste.
Stuff mushroom caps, packing the mixture firmly. Arrange mushrooms in shallow baking dish. Sprinkle tops with paprika. Bake for 25 to 25 minutes, or til mushrooms are tender. serves 6