01 - Combine warm milk, sugar, and instant yeast in a large mixing bowl. Let the mixture sit for 3–5 minutes until it becomes bubbly and foamy, indicating the yeast is active.
02 - Add sourdough discard, melted butter, egg, and salt to the yeast mixture. Stir thoroughly until all wet ingredients are fully incorporated.
03 - Gradually add flour, one cup at a time, mixing continuously. Stop when a soft, tacky dough forms—you may not need the full 4 cups. The dough should hold together without being overly dry.
04 - Turn the dough onto a lightly floured surface and knead for 7–8 minutes. The dough is ready when smooth, elastic, and springs back when pressed gently.
05 - Place the 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 1–1.5 hours.
06 - Punch down the risen dough and divide into 8 equal pieces. Roll each piece into a smooth 6-inch log, tapering the ends slightly for an even shape.
07 - Arrange the shaped logs on a parchment-lined baking sheet, leaving 2 inches of space between each. Cover and let rise until puffy and noticeably expanded, 30–45 minutes.
08 - Preheat the oven to 375°F while the buns complete their final rise.
09 - Brush the buns with milk and sprinkle with seeds if using. Bake for 18–20 minutes until golden brown on top and cooked through.
10 - Remove from the oven and immediately brush with melted butter for a softer crust. Allow the buns to cool completely on the baking sheet before slicing.