1Spray 24 mini muffin cups with cooking spray. In large saucepan, heat marshmallows, butter and cinnamon over medium-low heat about 2 minutes, stirring constantly, until marshmallows are melted. Remove from heat. Add cereal; stir until well coated.
2Spoon about 1 tablespoon cereal mixture into each muffin cup; press in bottoms and up sides of cups. Let stand until set.
3Just before serving, remove tarts from muffin cups. Top each with a small spoonful of yogurt and 1 berry.