Make yours now and keep it in the fridge until Christmas day. It's really very simple. For 8 people, beat together 6oz (175g) butter at room temperature and 6oz (175g) sugar until fluffy. Then add 5 tablespoons of brandy, one at a time. Substitute rum for brandy if you like; use salted or unsalted butter, and any kind of sugar. I used salted butter and unbleached caster sugar.