Cut two large oranges in half. Remove pulp with a spoon. Squeeze pulp and use the juice for step 3, adding additional juice as needed to reach 1/4 cup.
Rub zest of 1 orange (about 2 teaspoons) into the sugar. Add to cream and heat over medium just until simmering, 2 to 3 minutes.
Remove from heat and stir in orange juice and lemon juice. Pass through a fine mesh strainer to remove zest.
Divide cream mixture between the hollowed orange halves, filling generously. Refrigerate for 6 hours or overnight to set.
The next day, add chocolate chips, butter, and cream to a microwave-safe measuring glass. Heat in 30 second intervals, stirring between each, until chocolate is melted and mixture is smooth and glossy.
Pour the chocolate topping onto the chilled possets, spreading in a thin layer. Refrigerate again for 15 to 20 minutes before serving to allow chocolate layer to set. Enjoy!
