Poached Apricots in Vanilla-Thyme Syrup with Crème Fraîche

1 vanilla bean, halved lengthwise
3 cups water
2 cups Sugar
5 (3- by 3/4-inch) strips fresh Lemon zest
2 large sprigs fresh thyme
10 fresh apricots, halved and pitted (1 3/4 pound)
Accompaniment: crème fraîche
Scrape seeds from vanilla bean with tip of a sharp knife into a 2-quart saucepan and add pod, water, sugar, zest, and thyme sprigs. Bring to a boil, stirring until sugar is dissolved, then add apricots and simmer, stirring once or twice, until tender, 2 to 3 minutes (depending on ripeness).
Spoon syrup over warm apricots in bowls and top with dollops of crème fraîche.