Mix Dough (Night Before): In a large bowl, combine starter, warm milk, honey, and butter. Stir until smooth. Add salt and 2 ¾ cups flour. Mix until a shaggy dough forms. If needed, add more flour a tablespoon at a time until the dough is tacky but not sticky.
Knead by hand (8–10 minutes) or in a stand mixer (5–6 minutes) until smooth and elastic. Cover with a damp towel and let rest for 30 minutes.
Leave the dough to rise at room temperature (ideally 70–75°F) for 8–10 hours or overnight. It should double in size.
Turn the dough out onto a lightly floured surface. Divide it into 12 equal pieces and shape them into rolls. Place them in a greased 9x13 baking dish or on a parchment-lined sheet pan.
Cover and let rise 1–2 hours, until puffy and nearly doubled.
Preheat oven to 375°F (190°C). Bake rolls for 18–22 minutes, or until golden brown.
Brush with melted butter while warm. Sprinkle with flaky salt if desired.