Halve plum and discard pit, then cut each half lengthwise into 3 wedges.
Heat honey, 1/4 teaspoon cinnamon, and 1/8 teaspoon crushed anise seeds in an 8- to 10-inch ovenproof heavy skillet over moderate heat, stirring, until honey is liquefied, about 1 minute.
Add fruit to honey, tossing to coat, then transfer skillet to broiler and broil 6 inches from heat, turning fruit over once or twice and basting with pan juices, until fruit begins to soften and is glazed, 3 to 4 minutes.
Transfer fruit along with any pan juices to a dish.
Stir together sour cream, brown sugar, and remaining pinch each of cinnamon and crushed anise seeds, then spoon over warm fruit.