The marquee dessert at Golden Diner, in Manhattan’s Chinatown, is a take on tres leches, a Latin American cake soaked in three kinds of milk, as the Spanish name attests: whole milk, condensed milk and evaporated milk, its unsweetened cousin. Sam Yoo, the chef and owner, infuses the milk with Thai tea powder, a blend of black tea and vanilla that yields a signature tiger-orange hue. The longer the cake soaks, the better it is. (Mr. Yoo lets it rest for as long as two nights, with a flip in…