Tartine Bakery Sweet Potato Hamburger Buns – Cairnspring Mills

Ingredients

• 1/5 cup (45g) water, cool (70°F)
• 1/3 cup (72g) buttermilk, at room temperature
• 1 (45g) medium egg, at room temperature
• 1/3 cup (67g) leaven
• 1/3 cup (67g) poolish
• 3 teaspoons (13g) sugar
• 2 scant cups (266g) Edison flour
• 2 scant tablespoons (13g) buttermilk powder
• 1½ teaspoons (9g) salt
• 1 teaspoon (3g) instant yeast
• 3 scant tablespoons (40g) unsalted butter, at room temperature
• ½ small (80g) sweet potato, roasted and pureed