Melt butter in saucepan over medium heat; saute shallots for 5 minutes, add scallops, and cook 1 minute.
Add wine, thyme, and curry powder; cover, then reduce heat and simmer 5 minutes.
Do not overcook.
With slotted spoon, remove scallops to warmed serving dish.
Raise heat to bring liquid to a boil and cook until reduced by half.
Lower heat, combine 1 tablespoon of the yogurt and cornstarch, and blend with remaining yogurt.
Add to sauce; heat, stirring, for 2 minutes.
Pour sauce over scallops and serve.