Can be prepared in 45 minutes or less.

1/4 pound sea scallops, patted dry and cut into 1/2-inch-thick slices
1 tablespoon flour
2 tablespoons olive oil
1/4 cup dry white wine
2 tablespoons bottled clam juice
1 tablespoon minced shallot
1/3 cup fresh pink grapefruit juice
1/2 teaspoon grated pink grapefruit zest
1/2 teaspoon sugar
3 tablespoons cold unsalted butter, cut into bits
1 tablespoon thinly sliced scallions
fresh pink grapefruit sections for garnish

In a bowl toss together the scallops, the flour, and salt and pepper to taste. In a skillet large enough to hold the scallops in one layer heat the oil over moderately high heat until it is hot but not smoking and in it sauté the scallops, stirring, for 2½ to 3 minutes, or until they are just firm and lightly golden. Transfer the scallops to a plate. Add the wine to the skillet, deglaze the skillet, scraping up the brown bits, and stir in the clam juice, the shallot, the grapefruit juice, the zest, and the sugar. Boil the liquid until it is reduced to about 1/3 cup and strain the mixture through a fine sieve set over a saucepan. Set the pan over low heat and whisk in the butter, 1 at a time, lifting the pan from the heat occasionally to cool the mixture and adding each new bit of butter before the previous one has melted completely. (The sauce should not get hot enough to liquefy. It should be the consistency of thin hollandaise.) Add the scallion and the scallops with any juices that have accumulated on