Cover the bottom of a heavy-bottomed pot with the sugar. Add cream and juice.
Heat mixture over medium-high and leave it untouched. Don't stir.
It will bubble up and then eventually start to thicken. The mixture will start to look more syrupy and the bubbles will slow down. The whole process should take about 10-15 minutes.
Test that it's ready by putting a blob on a cold plate and dragging a line through it. If the line doesn't fill back in quickly, you're good to go.
Remove from the heat and stir in the salt, butter and gold dust (optional). Store in the fridge - it will firm up but you can warm it up again.
