Step 1
Adjust the oven rack to about 15 cm from the heat source and preheat the broiler.
Step 2
Place the grapefruit halves, cut-side up, on a baking sheet and sprinkle about 22.5 g of brown sugar over each half.
Step 3
Broil in the preheated oven until the brown sugar melts and starts to bubble, about 5 minutes. Allow it to cool for a few minutes before serving warm.