Check your starter. Make sure it’s active and bubbly. If it doubles within 4–6 hours of feeding, it’s good to go. If not, give it a feed and wait until it’s lively.

Mix wet ingredients. In a large bowl or stand mixer, combine warm milk, water, sugar (or honey), and sourdough starter. Stir until mostly smooth. Sprinkle in the instant yeast if using.

Add dry ingredients. Add 420 g of flour and the salt. Mix until a shaggy dough forms. Let it rest (autolyse) for 10 minutes to hydrate the flour.

Work in the butter. Add the softened butter and knead. In a stand mixer (dough hook), knead on medium-low for 6–8 minutes. By hand, knead 8–10 minutes. The dough should be soft, slightly tacky, and stretchy. If it’s too sticky, add flour 1 tablespoon at a time, up to 40 g more.

First rise (bulk ferment). Shape the dough into a ball and place it in a lightly oiled bowl. Cover and let it rise in a warm spot (75–80°F) until puffy and nearly doubled, 60–90 minutes with yeast, or 2–3 hours without. A warm oven (off) with the light on works well.

Prep the pan. Grease a 9x13-inch baking pan or a large round cake pan. You can also line with parchment for easy cleanup.

Divide and shape. Turn the dough onto a lightly floured surface. Divide into 12 equal pieces (about 70–75 g each). For smooth rolls, cup your hand over each piece and roll it against the counter in small circles to create surface tension.

Pan the rolls. Arrange the balls evenly in the pan with a little space between them. Cover loosely with plastic wrap or a damp towel.

Second rise. Let the rolls rise in a warm spot until noticeably puffy and touching, 45–75 minutes. They should jiggle slightly when the pan is tapped. Don’t rush this step—size and feel matter more than the clock.

Preheat the oven. Heat to 375°F (190°C) about 20 minutes before baking. For extra softness, place a small pan of hot water on the bottom rack to create gentle steam.

Bake. Brush the tops lightly with melted butter. Bake 18–22 minutes, until the rolls are golden brown and the centers read about 195–200°F on an instant-read thermometer.

Finish and cool. Brush with more melted butter right out of the oven for a soft, glossy finish. Cool in the pan for 10–15 minutes before serving warm.