*These ingredients are optional. Sugar will help the crust brown and lemon juice will prevent gluten from forming and giving you a tough crust. I generally leave these ingredients out, but they won’t hurt.

For the ice water, hold off on adding water until you add the starter. If the dough comes together when kneading, you might not need the water at all.

1. Grate the frozen butter on the widest setting of a cheese grater. Immediately freeze.
2. Whisk bread flour, salt, sugar* in a bowl.
3. Add sourdough discard and lemon juice*. Mix with a spatula until crumbly. Transfer dough onto counter.
4. Sprinkle in ¼ of the grated butter, then put butter back in freezer. Slowly drizzle in ice water until dough forms. Knead together, careful not to melt the butter.
5. Wrap the dough into a rectangle. Chill for at least 1 hr and up to 24 hrs.
6. You will do two letter folds with this dough. See instructions below:
7. Roll dough out into a rectangle, roughly 8-in x 4 in. Dough should be roughly 1/4-in thick.
8. Sprinkle 1/4 of frozen grated butter in center of rectangle. Then, take the right side of the dough and fold it over the butter. Sprinkle 1/4 of remaining butter on folded side. Fold the left side over newly sprinkled butter. Lightly press the edges down to seal butter in. Wrap and chill dough for 30-40 min.
9. Roll out dough to roughly triple its length (until 1/4-in thick again). Repeat step #8.
10. Your dough is now ready for assembling. Depending on your recipe, you want the puff pastry to be between 1/4 and 1/3-in thick.