Croissant Sourdough Bread

For the sourdough starter

1. Combine lukewarm water, ripe sourdough starter, and bread flour in a small bowl.

2. Stir until combined, cover, and let sit overnight at room temperature.

   Then 480 min of waiting

For the dough

3. Add the active sourdough starter into a large bowl.

4. Pour in lukewarm water, large egg yolk, table salt, granulated sugar, and bread flour into the bowl.

5. Stir to combine with a wooden spoon until a shaggy dough forms.

6. Transfer dough to an oiled container, cover, and let sit in a warm spot.

   Then 20 min of waiting

For the lamination

7. Wet your hands and perform a bowl fold by stretching the dough up and pressing into the middle, working around the dough 8 to 12 times.

8. Cover and let sit in a warm spot.

   Then 20 min of waiting

9. Wet a work surface with water to prevent sticking.

10. Turn the dough out onto the surface and stretch into a 14-inch rectangle.

11. Grate two-thirds of the frozen butter using a box grater over the surface of the dough.

12. Perform a letter fold by folding the left side over, then the right side over to create layers.

13. Grate the remaining third of frozen butter over the top.

14. Roll the dough up firmly from the far end toward yourself to form a log.

15. Place the dough back into the container, cover, and let sit.

    Then 30 min of waiting

16. Perform a coil fold by reaching underneath the dough, lifting it to stretch, and folding it back under itself. Repeat after turning 90 degrees.

17. Cover and let sit again.

    Then 30 min of waiting

18. Perform a second coil fold by lifting the dough from underneath and letting it fold over itself.

19. Cover the container and let bulk ferment at room temperature.

    Then 120 min of waiting

    The cold butter slows down fermentation, so give the dough ample time to become active before shaping.

To shape and bake

20. Flour your work surface generously with bread flour.

21. Turn the dough out onto the floured surface.

22. Fold the left and right sides inward to create a triangle-like shape, then roll down firmly from top to bottom to form a tight oval loaf.

23. Dust a lined banneton basket with flour.

24. Transfer the shaped loaf into the banneton, seam-side up, and pinch any loose seams together.

25. Cover the banneton and place in the refrigerator for cold proofing.

    Then 720 min of waiting

26. Preheat the oven to 475°F (245°C) with a baking stone inside and cast iron pans on the bottom rack for steam.

    Then 45 min of waiting

27. Fold the sides of a sheet of parchment paper to make a tray.

28. Place the parchment tray over the banneton and invert the loaf onto it.

29. Score the top of the loaf once down the center using a curved razor blade.

30. Slide the loaf on parchment onto the preheated baking stone, add water to the cast iron pans to generate steam, and close the oven door.

31. Bake until deep golden brown and crispy.

    Then 35 min of waiting

32. Transfer the loaf to a wire rack and let cool completely before slicing.

    Then 60 min of waiting

33. To adjust hydration for easier handling, reduce the water in the dough from 240 g to 210–215 g.

34. The parchment tray prevents melted butter from dripping onto the baking stone during baking.