Step 1

Combine the all purpose and cake flour with the salt and sugar. Whisk together to mix the ingredients evenly.

Step 2

Using your fingers, cut the shortening into the flo7aur mixture until it resembles coarse corn meal. Using your fingers, toss the butter into the flour mixture. Allow the slices of butter to break up into slightly smaller pieces into the flour. Work quickly so the butter doesn't get warm. Don't break the butter down completely. There should be some large flakes remaining.

Step 3

Pour the sourdough discard onto the flour all at once and toss to combine. Gently press the dough just until it comes together. It will look a little dry in spots. The moisture will redistribute in the dough as it rests.

Step 4

Wrap the dough and refrigerate for at least 2-3 hours before using.