Cookbook author Andrea Nguyen first sampled Vietnamese yogurt coffee in Hanoi years ago. To make it, Vietnamese-Style Homemade Yogurt is swirled with coffee and sweetened condensed milk to make a drink that's creamy, tangy, and bittersweet with a caffeinated boost. This refreshing drink is best presented in a tall, slender glass. The yogurt starts out floating on top; when stirred, there's a beautiful marbled effect. Employ inky, robust coffee made from a dark or medium-dark roast for Viet flair. For a more generous serving, simply double the recipe.