Microwave cream cheese in a 1-quart microwave-safe bowl at HIGH 20 seconds. Stir in Parmesan cheese and next 4 ingredients.
Cut bread in half lengthwise; spread cream cheese mixture over cut sides of bread. Top with tomato. Place on a baking sheet, cut side up.
Broil 5 1/2 inches from heat (with electric oven door partially open) 4 to 5 minutes. Cut into slices.
The Best of Mr. Food: Dinner on the Double
