Prepare your ramekins by placing them on a sheet pan for easy transport.

In a medium bowl, combine granulated sugar and orange zest, rubbing them together for about 1–2 minutes.

In a medium saucepan, combine the heavy whipping cream with the orange-sugar mixture over medium heat and stir until it comes to a gentle boil.

Squeeze fresh oranges to yield ½ cup of juice and strain it to remove any pulp and seeds.

Once the cream has simmered, strain it and stir in the freshly squeezed orange juice, allowing it to cool for 20 minutes.

Evenly distribute the cooled orange cream mixture into the prepared ramekins and chill in the refrigerator for at least 1 hour.

For the ganache, place chopped semi-sweet chocolate and heavy whipping cream in a microwave-safe bowl, heating in 30-second bursts until smooth.

Spoon the warm ganache over each set posset and return to the fridge for a final chill until the ganache is set.