Add brandy or rum depending on personal preference or what you have available - they're both delicious.
Melt the butter and stir in the flour. Cook for 2 minutes and then stir in the milk. Bring to the boil, stirring all the time, and simmer gently for 10 minutes.
Stir in the brandy (or rum) and the sugar and serve with Christmas pudding.
You can make this using cornflour instead of making a roux, but the results aren't as creamy.
