Use your starter in the summer with these naturally leavened hamburger buns!
Place all of the dough ingredients in the bowl of a stand mixer. Knead on medium-low for 15 minutes, or until the dough is quite elastic. The dough should clean the sides of the bowl, but not the bottom. Add more flour as needed to achieve that consistency.
Place the dough in a buttered bowl, turning once to grease the top of the dough. Cover and allow to rise for 6-12 hours, or until doubled in bulk.
Plop the dough onto a greased work surface. Divide the dough into 12 equal pieces. Grab a piece of dough and pull the corners into the middle to start forming a ball. Cup your hands around the ball and roll it across your work surface to create surface tension.
Place the ball on a greased cookie sheet. Flatten into a bun shape. Repeat with the remaining dough pieces. You may need to use more than one cookie sheet.
Cover with a tea towel and allow to rise for 2-6 hours, or until the buns are quite puffy.
Preheat oven to 375 degrees F.
In a small bowl, whisk an egg. Brush the tops of the buns with the egg. Sprinkle sesame seeds on top.
Bake in preheated oven for 25-30 minutes, or until golden brown. Remove from oven and place on a wire rack to cool before slicing.