Lightly caramelized fruit makes for a great, healthy start to your day.
Heat broiler with rack set 4 inches from heat. With a paring knife, loosen grapefruit segments from membranes and pith.
Sprinkle grapefruit with sugar and cinnamon. Broil on a baking sheet until tops are slightly browned, 4 to 5 minutes.
Top with yogurt, and garnish with more cinnamon.