Combine 1/2 cup balsamic vinaigrette and mushrooms in a heavy-duty zip-top plastic bag. Chill 2 to 3 hours. Drain mushrooms well, and place on a baking sheet.
Broil 5 inches from heat (with electric oven door partially open) 3 minutes; turn mushrooms over, and broil 5 more minutes or until tender.
Cut mushrooms into thick slices, cutting to but not through opposite side.
Arrange salad greens on individual plates; top with walnuts, goat cheese, and mushrooms. Drizzle evenly with remaining 1/2 cup vinaigrette. Serve with Parmesan cheese toast.
*1 (8-ounce) bottle Italian dressing may be substituted.
NOTE: For testing purposes only, we used Newman's Own Balsamic Vinaigrette.