Line a 12-cup muffin pan with paper liners.
Pour 2 teaspoons of the melted chocolate into each cup. Use a spoon to spread it across the bottom and a little up the sides.
Freeze for 10 minutes until set.
Pour 1 tablespoon of melted chocolate into each cup. Use a spoon to spread it and then sprinkle with flaky sea salt. Do this one cup at a time.
Freeze for 10 minutes until set.