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 lightly floured surface and knead for 7–8 minutes until smooth and elastic.
05 - Place dough in a lightly greased bowl, cover, and let rise until doubled in size, approximately 1 to 1.5 hours.
06 - Punch down dough and divide into 8 equal portions. Shape each piece into a smooth log about 6 inches long.
07 - Arrange shaped buns on parchment-lined baking sheet, spacing 2 inches apart. Cover and let rise until puffy, 30–45 minutes.
08 - Preheat oven to 375°F during the final rise period.
09 - Brush buns with milk and sprinkle with seeds if using. Bake for 18–20 minutes until golden brown.
10 - Remove from oven and immediately brush with melted butter for softer crust. Cool completely before slicing.