Warm the butter until just melted. Mix with the golden syrup and brown sugar. Fold in the rest of the ingredients. Place a tablespoon of marmalade into a dariole mould, a ramekin or a small pudding basin. (You could make one large pud rather than individuals, just up the cooking time to a couple of hours.) Pour the mixture on top to about two thirds full and then either pop a lid on top or seal with foil. Steam over boiling water for around 45 minutes until a skewer comes out clean. You can microwave the puds but you need to use a much smaller quantity of the mixture as it expands so much!
Serve the puddings with cream, creme fraiche, ice cream or even lashings of custard.