Boreka Dough

Makes 3 pastry sheets (roughly 10 by 15 inches each); 1 sheet makes about 8 borekas

● Combine the flour, salt, and vinegar in the bowl of a stand mixer fitted with the paddle attachment. Mix on low while adding the seltzer in a slow, steady stream. Continue mixing until the dough begins to pull away from the sides and bottom of the mixer, about 2 minutes.

● Flour a work surface and knead the dough by hand just until it feels smooth and homogenous, about a minute. Cover with a clean cotton cloth and let rest for 30 minutes.

● Working with a floured rolling pin, roll the dough out to a rough ¼-inch-thick rectangle with a long side facing you. (It should be at least 20 by 15 inches.) Spread half the butter evenly across the middle third of the dough rectangle. Fold the left third of the dough over the butter, then fold the right third over the left third (they’ll overlap). Fold the top and bottom edges toward the center the same way, forming a square. Wrap tightly with plastic wrap and refrigerate overnight.

● Flour a work surface. Orient the dough square so that it’s turned 90 degrees from the first time you folded it (that is, with the folded ends on the sides). Roll the chilled dough out to a ¼-inch-thick rectangle (again, about 20 by 15 inches). Spread the rest of the butter evenly across the middle third of the rectangle. Fold the sides over the butter, and fold the top and bottom toward the center, forming a square. Wrap tightly with plastic wrap and refrigerate overnight.

● Flour a work surface. Orient the dough square so that it’s turned 90 degrees from the last fold and roll the chilled dough out to a ¼-inch-thick rectangle. Repeat the folding process, folding the sides into the center and then folding the top and bottom toward the center to make a square. (This time, don’t add more butter.) Wrap tightly with plastic wrap and refrigerate overnight.

● The next day, divide the dough into 3 pieces and freeze for later use; or, roll each piece into a 10-by-15-inch sheet to use in recipes. Make sure to keep the dough cold at all times (except when you’re working with it).

● Filled borekas can be frozen before baking. In that case, put them directly in a preheated 425°F oven; don’t thaw them first.

● Don’t refrigerate baked borekas. They’ll keep at room temperature for 2 days. Reheat in a 325°F oven for 5 minutes.