Transfer the mixture to a bowl, then add the sour cream and gently fold it in by hand. If the dough is dry, add 1 tablespoon more of sour cream at a time until it comes together.
Remove the dough from the freezer and turn it so the long side is facing you. Roll it out to a ¼- to ½-inch-thick square again, then fold it into thirds the same way.
oll out the dough once more to ¼-inch thickness. Use a round cookie cutter to cut out circles from the dough. Press the circles into the mold, creating little cups.