In the bowl of a stand mixer fitted with a dough hook, add water, yeast, and 1 tablespoon of the granulated sugar. Stir together, then let the yeast rise for about 5-10 minutes. In a small bowl, whisk together buttermilk, egg, and oil until well-combined. After 10 minutes, the yeast should look frothy and bubbly. At this point, pour in the buttermilk mixture, remaining sugar, and salt, and stir together for 10-15 seconds.