Deluxe Steak Sandwich, The Healthy Way from Lighter, Quicker, Better: Cooking for the Way We Eat Tod

Ingredients

• 2 French rolls or an 8-inch length French or Italian bread, split
• 6 large mushrooms, sliced
• 1 tablespoon chopped parsley
• ½ cup water
• 1 garlic clove, halved
• Dijon mustard
• 1 teaspoon olive oil
• 1 slice (6 ounces) filet mignon, well trimmed
• ½ small onion, cut into slivers
• Salt
• Freshly ground black pepper
• Watercress or arugula sprigs