Cardamom's warmth and slightly citrusy flavor is a perfect match to orange panna cotta.
In pot, bring 1/3 cup sugar, 1/3 cup water, and cardamom to boil, stirring until sugar dissolves. Reduce heat to low; simmer for about 5 minutes. Strain syrup into bowl; let cool. Zest 1 orange. Juice all 3 oranges; strain enough juice into bowl to measure 1 cup. Whisk in gelatin. In same pot, bring cream and remaining 1/3 cup sugar to boil. Off heat, whisk orange juice into cream; divide among 8 greased 4-oz. ramekins. Refrigerate panna cotta until set, about 2 hours. Unmold panna cotta. Drizzle with syrup. Garnish with orange zest and chocolate.