01 - Combine warm milk, sugar, and instant yeast in a large mixing bowl. Let stand for 3 to 5 minutes until mixture becomes bubbly and foamy.
02 - Add sourdough discard, melted butter, egg, and salt to the yeast mixture. Stir until thoroughly incorporated.
03 - Gradually add flour, one cup at a time, mixing until a soft and tacky dough forms. Stop adding flour when dough reaches proper consistency—you may not need the full amount.
04 - Turn dough onto a lightly floured surface and knead for 7 to 8 minutes until smooth and elastic, adding minimal flour only if sticking excessively.
05 - Place dough in a lightly greased bowl, cover with plastic wrap or a clean towel, and let rise in a warm, draft-free area 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 approximately 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 expanded, 30 to 45 minutes.
08 - Preheat oven to 375°F while buns complete their final rise.
09 - Brush buns lightly with milk and sprinkle with seeds if using. Bake for 18 to 20 minutes until golden brown on top.
10 - Remove from oven and immediately brush with melted butter for a softer crust. Allow buns to cool completely on a wire rack before slicing.