On National Vanilla Milkshake Day in June 2018, Serendipity 3 unveiled its ultra-luxurious take on the classic. And it’s no ordinary vanilla milkshake, with an ingredient list that includes Jersey milk, Tahitian vanilla ice cream, Madagascan vanilla beans, Devonshire clotted cream, artisan caramel sauce and, of course, an obligatory scattering of gold. Created in partnership with Swarovski and Crystal Ninja, it’s also served in a crystal-studded milkshake glass. If you’re willing to shell out $100 (£74) for the privilege, you can try it for yourself.