Soft, squishy buns that hold up to the juiciest burgers. Once you make your own, you'll never go back to store-bought.

Combine the starter, warm milk, egg, melted butter, and sugar in a large bowl.
Add the flour and salt. Mix until a dough forms, then knead for 8-10 minutes until smooth and elastic.
Place in a greased bowl, cover, and let rise for 4-5 hours at room temperature until doubled.
Punch down and divide into 8 equal pieces (about 95g each).
Shape each piece into a tight ball, then flatten slightly into a disc about 3.5 inches wide.
Place on a parchment-lined baking sheet, spacing 3 inches apart. Cover and refrigerate overnight.
The next morning, remove from the fridge and let rise for 1.5-2 hours until puffy.
Preheat oven to 375°F (190°C).
Brush tops with egg wash and sprinkle with sesame seeds if using.
Bake for 15-18 minutes until golden brown.
Let cool completely on a wire rack before slicing.