In the bowl of a stand mixer, combine starter and water.
Mix until smooth.
Mix until combined.
Switch to dough hook.
Add flour and salt.
Mix on low speed until ingredients are combined, about 1 minute.
Increase speed to medium.
Knead until dough is smooth, about 8 minutes.
Turn dough into a clean bowl.
Proof at warm room temperature (78° F) until increased by 25%, about 2 hours. (If not using a proofing box with a humidity tray, cover your bowl with plastic wrap.)
Turn dough out onto unfloured surface.
Divide into 4 ounce pieces.
Roll each piece of dough into a ball.
Cover and let rest 5 minutes.
While dough is resting, line 2 sheet pans with parchment and spray lightly with cooking spray. Set aside.
Beginning with the first piece of dough you formed into a ball, use a floured thumb to push through the center of the dough ball.
Insert other thumb and work around.
As the center circle increases, use your index fingers to twirl it around until you have a large (3 inch) center hole.
Place on prepared sheet pan - 6 on one, 5 on the other.
Cover pans with plastic wrap that has been sprayed with cooking spray.
Allow to proof until increased by 25%, about 1 hour.