3/4 cup sauerkraut, drained and squeezed dry
1/3 cup thousand island salad dressing
1 (8 ounce) tube refrigerated crescent rolls (such as Pillsbury(R))
3/4 pound thin-sliced cooked corned beef
8 slices Swiss cheese
1 beaten egg white
Preheat oven to 375 degrees F (190 degrees C). Grease an 8×8-inch baking dish.
Mix together the sauerkraut and thousand island salad dressing in a bowl until well combined. Unroll the crescent roll dough, and cut dough in half; place one half of the dough onto a floured work surface, and pinch the perforations of the dough closed to make 1 sheet. Roll the dough sheet out to about 12 inches square, and fit the dough into the prepared baking sheet. Pinch perforations closed on 2nd half of dough; roll out to about 9 inches square, and set aside.
Prebake the dough crust in the baking dish in the preheated oven until lightly browned, 8 to 10 minutes. Remove from oven, and place 4 slices of cheese into the bottom of the crust; top cheese slices with the corned beef, and spread with the sauerkraut mixture. Lay 4 remaining slices of Swiss cheese on top of the sauerkraut mixture. Lay the 2nd sheet of crescent roll dough onto the filled baking sheet, and press the top crust down onto the edges of the dish to seal. Brush with beaten egg white.
Bake in the oven until the cheese is melted and the crust is golden brown, 15 to 20 minutes; let stand about 5 minutes before slicing.