01 -
Slice the grapefruit through the equator and place the halves cut side up on a foil-lined baking sheet. Run a paring knife around the edge where the fruit meets the rind, then cut between the segments so the flesh is easy to scoop.
02 -
Stir together the brown sugar and cinnamon. Sprinkle the mixture evenly over the cut surface of each grapefruit half.
03 -
Place the baking sheet under a hot broiler about 4 to 6 inches from the flame. Watch closely and broil for 3 to 5 minutes, until the sugar is melted, bubbly, and just beginning to caramelize at the edges. Remove and let cool for a minute before serving.