Preheat the grill on high. Place the grapefruit halves cut-side up on a baking sheet.

In a small dish, stir together the almonds, honey and cinnamon. Spoon an equal amount of the topping over each grapefruit half.

Grill for 5 to 7 minutes or until the topping begins to brown and the fruit is plump and warm.

Add the Fage yoghurt and serve.