Feed your sourdough:

1. The evening before you plan to make the cruffin, feed your sourdough with equal parts water and flour and let it rest up to 8 hours at warm room temperature.

Final Dough:

1. The next morning, mix the milk into the sourdough to break it up.
2. In a large bowl, whisk together the flour, sugar, and salt. Work the chilled butter pieces into the flour using your fingers.
3. Pour the milk/sourdough mixture over the flour mixture and mix into a soft and elastic dough that comes away from the side of the bowl. The dough should not be sticky. Add a little more milk or flour, as required to achieve this consistency of dough.
4. Shape the dough into a ball and transfer it to back to the bowl. Cover and let the dough rise till double in volume. This should take between 2-3 hours, depending on ambient temperature.
5. Stretch and fold the dough two times – once after 30 minutes and again after the first hour.
6. Prepare your baking pan and keep aside. Butter and very lightly flour the cavities of your muffin or popover tray.
7. Dust your working surface lightly with flour and turn the dough out. Lightly knead to deflate the dough. Divide into four equal pieces. Roll out each piece to a 24 x 8 inches (60x20cm) sized piece. The dough sheet should be very thin.
8. Spread about 30 to 38 gm butter (depending on whether you’re using 120 gm or 150 gm of butter) of soft butter over each rolled out piece of dough. Cut each piece into half, lengthwise, creating two thin strips.
9. Roll one thin strip into a tight roll. Place this at the edge of the second strip and continue rolling till you have one thick roll. This will give your cruffins more layers.
10. Cut roll in half lengthwise. Roll each half, like a circle (cinnamon roll style) with the cut layers side showing the outside. Make sure to tuck both ends under so it doesn’t open up on baking. Place the roll in the prepared muffin or popover pan.
11. Repeat with all the dough pieces. Cover the pan with a kitchen towel and allow to rise for 3-4 hours, depending on ambient temperature and if the dough was cold fermented. The rolls should look puffy and have risen to almost the edge of the cavities.
12. Bake the cruffins at 190C (375F) for about 30 minutes or till golden brown and done. Turn them out onto a rack and let the cool. Dust with icing sugar or brush tops the with melted butter and dredge in cinnamon sugar. Serve warm with coffee or tea.