Grill 'n' Shake took everyone's favourite diner drink to a whole new level in 2015, launching the Millionaire’s Milkshake, priced at £50 (around £66/$83 in today's money). The restaurant, which has since closed, packed the shake with rich Jersey milk, saffron strands and ice cream made using Tahitian vanilla pods. It was topped off with 23-carat edible gold leaf sprinkles, black truffle shavings and Italian Amedei chocolate (some of the most expensive chocolate in the world).