Carefully combine yogurt, raspberries, milk and mint in small bowl; set aside.
Combine spinach, mushrooms and sesame seeds in medium bowl; mix well.
Arrange spinach mixture evenly on 2 individual salad plates; top with red onion rings.
Drizzle yogurt dressing over salads; sprinkle with bacon.
Garnish with fresh raspberries and mint sprig, if desired.