In a 2-quart saucepan over medium heat, melt the butter. Add the sugar, brandy, cinnamon, and salt and whisk to combine. Cook at a simmer, whisking, until the sugar is dissolved and the mixture is light in color and foamy. Remove from the heat.

In a small bowl, beat the egg until frothy, then gradually whisk it into the mixture in the saucepan.

Return the pan to medium heat and cook for about 2 minutes, stirring constantly, until thickened.

Stir in the cream and remove from the heat.

Keep at room temperature for up to 4 hours, until ready to use; or cover and refrigerate, then reheat in a microwave oven and stir in a few teaspoons of water to thin the sauce a bit.