Homemade Sourdough Burger Buns - Grit

Ingredients

• 3/4 cup prepared sourdough starter
• 3/4 cup lukewarm water
• 1 teaspoon instant yeast
• 2 cups all-purpose flour
• Scant 1/3 cup whole-wheat flour
• 2 tablespoons potato flour
• 2 tablespoons dry milk
• 1-1/2 teaspoons salt
• 1 tablespoon sugar
• 4 tablespoons softened unsalted butter
• 1 egg, for wash (optional)
• 1 teaspoon water, for wash (optional)
• Sesame seeds (optional)