Early versions of the Jockey Club called for Crème de Noyaux, a difficult-to-find almond liqueur that has only recently been re-introduced to the wider spirits market.
Crème de Noyaux isn’t for everyone; it has an herbal undercurrent that some folks find off-putting. This tweaked version from mixologist gaz regan calls for amaretto instead, and updates the proportion for a flavor more suited to modern tastes. That said, if you’re a fan of Crème de Noyaux, do give it a shot here!