DIRECTIONS
Using a sharp knife, peel the grapefruit, removing all of the bitter white pith.
Working over a bowl, cut in between the membranes to release the sections.
Squeeze the juice (approximately 3 TBSP.) from the membrane into another bowl.
In a large skillet, cook the bacon over moderate heat until crisp, 3 minutes.
Using a slotted spoon, transfer it to a small plate.
Pour off all but 1 TBSP. of the bacon fat.
Season the scallops with salt and pepper and add to the skillet.
Cook over moderately high heat until browned, 3 minutes.
Turn the scallops, add the onion and cook over moderate heat until the scallops are just cooked through, 3 minutes longer. Transfer to a plate.
Add the wine and grapefruit juice to the skillet and bring to a simmer over moderate heat.
Cook, scraping up any browned bits.
Strain the liquid into a heatproof cup, then return it to the skillet.
Add the capers and butter and cook, shaking the pan, until the sauce is thickened, 2 to 3 minutes.
Add the scallops and any juices to the skillet.
Turn the scallops to coat them with the sauce.
Add the grapefruit sections and bacon and serve right away.