Marinade: Measure mustard into a bowl. Whisk in vinegar, sugar, salt, pepper and chives. Continue to whisk mixture while slowly dribbling in olive oil until mixture thickens. Adjust seasoning to taste. Mushrooms: Combine mushrooms and marinade in a zip lock bag; refrigerate for 4 to 6 hours. Grill mushrooms for 6 to 8 minutes each side and set aside to cool. Preheat oven to broil. Put a small amount of olive oil in a large skillet and sauté onions and garlic until tender (3 to 5 minutes). Add spinach, tomatoes and lemon juice and sauté until spinach wilts (3 to 4 minutes). Sprinkle with Tabasco. Salt and pepper to taste. Place cooled Portobellos (top side down) on baking sheet and sprinkle each with Parmesan cheese. Mound spinach mixture onto each mushroom, dividing evenly among the mushrooms and sprinkle with Parmesan cheese. Place pan under broiler for 5 minutes or until mushrooms are hot and sizzling. Serve immediately. Yield: 4 servings. |