Making the ultimate gourmet grilled cheese sandwich is no small task. It should be one treated with care, giving each ingredient their time to shine. The bread, cheeses, vegetables, and herbs all need to coexist perfectly to lend the ideal balance of flavors. The secret to this Ultimate Gourmet Grilled Cheese Sandwich is to use the finest, freshest ingredients. The sourdough bread should come straight from your favorite bakery. Real butter must be used to cook it in- no margarine for this sandwich. Grate the cheeses yourself for the stringiest, gooiest cheese imaginable. Fresh onions and herbs will round out…