In a large mixing bowl, combine the sourdough starter, warm milk, melted butter, honey, and egg. Mix until smooth.
Gradually add the flour and salt, mixing until a soft dough forms.
Knead the dough by hand or with a stand mixer for 8–10 minutes, until smooth and slightly tacky.
Place the dough in a greased bowl, cover, and let rise at room temperature for 8–12 hours, or until doubled in size.
Turn the dough out onto a lightly floured surface and divide into 8–12 equal portions. Shape each portion into a smooth ball.
Place rolls on a parchment-lined baking sheet, spaced evenly apart. Cover loosely and let rise for 1–2 hours, until puffy.
Preheat oven to 375°F (190°C).
Optional: Brush tops with egg wash for a golden finish.
Bake for 18–22 minutes, or until golden brown.
Remove from oven and let cool slightly before serving.