Gather your ingredients so that you have everything close at hand on the counter or table.
Step 1 - Make the Dough
Using a large mixing bowl, combine the all-purpose flour, sourdough starter, water, softened butter, and kosher salt. Mix together using a dough whisk or wooden spoon until the dough comes together and all the flour is mixed in. Add more water by tablespoons if needed for the dough to form a ball.
Place the dough in a bowl coated in cooking spray or olive oil. Cover with plastic wrap and refrigerate for 8-20 hours.
Step #2 - Prepare the Butter Layers
Cut two 12" x 12" pieces of parchment paper and lay one on the counter or workspace. Slice the cold butter into tablespoons and lay them on one half of the paper to form a square. Place the second piece of parchment paper over the top to cover the butter.
Using a rolling pin or the flat side of a meat tenderizing mallet, beat the cold butter to flatten and warm it, Continue beating it until it has flattened and spread to form an 8" x 8" square. The butter should be firm by pliable at this point. Place in the refrigerator until ready to use.
Step #3 - Laminating the Dough
Take the cold dough from the refrigerator and place it on a lightly floured workspace. Using a rolling pin, gently roll the dough into a square that is 12" x 12".
Remove butter from the refrigerator and take off the top piece of parchment paper from the butter. Place the button on the dough so that it's a diamond on a square. Peel off the remaining piece of paper.
Fold the corners of the dough to meet in the center and cover the butter. Pinch the ends together to seal, then lightly tap the dough with the rolling pin to flatten and secure the seams. You should now have a butter-enclosed dough square that is 8" x 8".
Step #4 - Turning the Dough
Using a rolling pin, roll the dough into an 8" x 24" rectangle. Roll gently so you don't manipulate the butter too much. (You want the butter to stay in one layer and not get clumped up.)
Fold the right 1/3 of dough toward the middle, and then fold over the left 1/3 of dough like a trifold letter. This is called the "first turn."
Pivot the dough 90 degrees so that the sides are now the top and bottom. Using a rolling pin, roll out the dough to form an 8" x 24" rectangle. Once more, fold the dough in thirds like a letter. This is the "second turn."
Cover the folded dough in plastic wrap or waxed paper freezer bag and refrigerate for at 30 minutes.
After the resting time, roll the dough into an 8" x 24" rectangle and fold the dough like a letter. This is the "third turn." Repeat as before for a "fourth turn." (If any butter pops through the dough, simply rub some flour on it and press it back into the dough.) Place the dough in plastic wrap or waxed paper and refrigerate for 30 minutes.
Repeat the rolling and folding for the final two turns. You will now have turned the dough a total of six turns. Place the dough in the plastic wrap or waxed paper and refrigerate for at least 2 hours. You may also freeze it at this point, if desired, for up to 4 months.
To use, roll dough to 1/8" - 1/4" thickness and cut into desired shapes. Bake in a preheated 400℉ oven for 15-20 minutes until crisp and golden brown. If using frozen dough, be sure to thaw it out in the refrigerator before rolling.
Notes
*Unless otherwise indicated, all butter used on this recipe site is salted.**If unable to find European butter, simply use regular butter. ***If desired, you may cut this recipe in half, following directions as written with the exception of rolling the dough into 8 x 12 - inch rectangles when turning the dough instead of 8 x 24 - inch rectangles.