Clementines in Ginger Syrup

Bring water, sugar, ginger, cardamom, and star anise to a boil in a small saucepan over medium-high heat, stirring until sugar has dissolved, then simmer, uncovered, stirring occasionally, 10 minutes.

Remove from heat and let steep, covered, 15 minutes. Strain syrup through a sieve into a bowl, discarding solids. Chill, covered, until cold, at least 2 hours.

Cut peel from clementines, including all white pith, with a sharp knife, then cut fruit into 1/4-inch-thick rounds and put in a serving bowl. Add syrup and chill, covered, at least 1 hour. Just before serving, sprinkle with pomegranate seeds (if using).