• Heat the milk just until warm, then remove from heat. Add the butter and stir until melted. Set aside and allow the mixture to cool until lukewarm. (In a pinch, you can just put the butter and milk in a bowl together in the microwave for short bursts until the butter is mostly melted, stirring after every 20seconds or so).

Combine the Ingredients

• In a large bowl (or the bowl of a stand mixer), combine the flour, starter, and butter/milk mixture.
• Mix by hand until just combined. Cover and let rest for 30 minutes.
• Add the sugar, salt, eggs and oil to the mixing bowl and using a dough hook, mix until smooth and elastic. Dough should pass the windowpane test, but may need to rest for 10min before passing the test.

Bulk Fermentation

• Cover and let the dough rise until doubled in size, about 8–12 hours, depending on room temperature and starter activity. Overnight fermentation works very well for this recipe.

Shape

• Divide the dough into 15 equal portions (approx. 75g each) and shape into smooth balls. To shape, pinch the edges up and into the centre and the flip it onto the counter (seam side down) and cup your hand over it and start circling it to form a tightly shaped "ball".
• Lightly spray or grease your baking pan and arrange the dough balls evenly.

Final Rise

• Cover and let rise again for another 6–8 hours, until the buns are puffy and have risen (they should fill the pan now).

Bake

• Preheat oven to 350°F
• Bake for 12–15 minutes, until lightly golden. If the buns don’t sound hollow when flicked, return them to the oven for an additional 3–5 minutes.