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 a clean towel, and let rise in a warm spot 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, tapering the ends slightly.
07 - Arrange shaped buns on a parchment-lined baking sheet, leaving 2 inches of space between each. Cover and let rise until puffy and doubled, 30–45 minutes.
08 - Preheat oven to 375°F while buns complete their second rise.
09 - Brush buns with milk and sprinkle with seeds if using. Bake for 18–20 minutes until deep golden brown and internal temperature reaches 190°F.
10 - Remove from oven and immediately brush with melted butter for a softer crust. Transfer to a wire rack and cool completely before slicing or serving.