01 - In a large mixing bowl, combine the warm milk, sugar, and yeast. Let sit for 3–5 minutes until bubbly and foamy.
02 - Add the sourdough discard, melted butter, egg, and salt to the yeast mixture. Mix until well combined.
03 - Gradually add flour, 1 cup at a time, mixing until a soft, tacky dough forms. You may not need all the flour depending on humidity.
04 - Knead the dough on a lightly floured surface for 7–8 minutes until smooth, elastic, and no longer sticky.
05 - Place the dough in a lightly greased bowl, cover with plastic wrap or a damp towel, and let rise until doubled in size, about 1 to 1.5 hours.
06 - Punch down the dough and divide into 8 equal pieces. Shape each piece into a smooth log about 6 inches long, tapering the ends slightly.
07 - Place shaped buns on a parchment-lined baking sheet, spaced 2 inches apart. Cover and let rise until puffy, 30–45 minutes.
08 - Preheat oven to 375°F during the final 15 minutes of the second rise.
09 - Brush buns with milk and sprinkle with seeds if desired. Bake for 18–20 minutes until golden brown on top.
10 - Remove from oven and immediately brush with melted butter for a softer crust. Cool completely on a wire rack before slicing.