Different versions of this traditional Christmas favourite provide an unexpected insight into the British class system. The people's favourite is Waitrose Remy Martin Brandy Butter (150g, £2.65, pictured). It's a fairly brash affair but a hefty slug of brandy asserts its authority over sugary butter. Plutocrats should send the Rolls round to Harrods for Limited Edition Brandy Butter (220g, £7.50): primrose-yellow, smooth, slightly salty with a potent alcoholic buzz. Fortnum's Cognac Brandy Butter (210g, £3.95) is another class act. Pale and seductive, it is the English Rose of brandy butters, exhibiting desirable restraint in the sweetness department.