To Make the Dough: In a large bowl, stir together the lukewarm water, sourdough starter, and salt.
Add in the flour, use your hand like a spatula to mix until the flour is completely incorporated. (There should not be any dry spots of flour left.) Cover with a kitchen towel or saran wrap, then set aside at room temperature for 30 minutes.
The First Fold: After the first rest, it’s time for the first fold. Remove the cover, then gently pull up one side on the dough to then fold over into the center. Turn the bowl slightly and repeat. Repeat the pull & fold method a total of 8 times. Then, cover and rest for 30 minutes.
The Second Fold: After the second rest, repeat the pull and fold method same as before, then rest an additional 30 minutes. (You will have done the pull and fold method for a total of 3 times.) By the end, the dough should be more smooth and elastic. If not, repeat one more time.
The Final Rise: Cover the dough with saran wrap to set out at room temperature for 4-16 hours, until doubled in volume. (The timining will depend on the time of year, and strength of your sourdough. For instance, you can start this dough early morning during the hot summer months and have it ready by the evening. During winter months, I’ll let it rise on the counter overnight.)