Cardamom Milk Pudding

Bring milk, cardamom pods, and a pinch of salt just to a boil in a 2-quart heavy saucepan, then remove from heat and let stand, covered, 5 minutes.

Whisk together arrowroot and sugar in a large bowl, then whisk in hot milk mixture. Return to saucepan and simmer, stirring constantly, until thickened, about 2 minutes. Strain through a fine-mesh sieve into a bowl, discarding solids. Chill pudding, its surface covered with wax paper, until very cold, at least 4 hours. Serve sprinkled with nuts.