01 - Combine warm milk, sugar, and yeast in a large mixing bowl. Let sit for 3–5 minutes until mixture becomes bubbly and foamy.
02 - Add sourdough discard, melted butter, egg, and salt to the yeast mixture. Stir until thoroughly combined.
03 - Gradually incorporate flour, one cup at a time, mixing until a soft, tacky dough forms. Stop adding flour once dough reaches proper consistency—you may not need the full amount.
04 - Turn dough onto a lightly floured surface and knead for 7–8 minutes until smooth, elastic, and no longer sticky.
05 - Place dough in a lightly greased bowl, cover with plastic wrap or damp towel, and let rise in a warm place until doubled in size, approximately 1 to 1.5 hours.
06 - Punch down risen dough and divide into 8 equal portions. Roll each piece into a smooth log about 6 inches long.
07 - Arrange shaped buns on a parchment-lined baking sheet, leaving 2 inches of space between each. Cover and let rise until puffy, 30–45 minutes.
08 - Heat oven to 375°F during the final stages of the second rise.
09 - Brush buns with milk and sprinkle with seeds if using. Bake for 18–20 minutes until deep golden brown.
10 - Remove from oven and immediately brush with melted butter for a softer crust. Allow to cool completely before slicing and serving.