Orange Posset

Combine citric acid and water in medium bowl and stir until acid is completely dissolved. Transfer solution to airtight container until ready to use.

Combine ½ teaspoon citric acid solution and orange juice in small bowl; set aside. Combine cream, sugar, and orange zest in medium saucepan and bring to boil over medium heat. Continue to boil, stirring frequently to dissolve sugar. If mixture begins to boil over, briefly remove from heat. Cook until mixture is reduced to 2 cups, 8 to 12 minutes.

Remove saucepan from heat and stir in orange juice mixture. Let sit until mixture is cooled slightly and skin forms on top, about 20 minutes. Strain through fine-mesh strainer into bowl; discard zest. Divide mixture evenly among 6 individual ramekins or serving glasses. Refrigerate, uncovered, until set, at least 3 hours or up to 2 days (if chilling for more than 3 hours, cover each ramekin).

When ready to serve, uncover possets, if needed, and let sit at room temperature for 10 minutes. Garnish possets with chocolate shavings and serve.