Heat oven to 375˚. In food processor bowl with metal blade, place corned beef, cheese, sauerkraut and mustard. Cover and process until finely chopped.
If using crescent rolls: Unroll dough and separate into 4 rectangles. Press each into 7.5×5″ rectangle, firmly pressing perforations to seal. Cut each rectangle into 6 squares. If using dough sheet: Unroll dough and cut it into 4 rectangles and follow instructions above.
Place 1 teaspoon corned beef mixture on each square. Fold one corner to opposite corner, forming triangle and pressing edges to seal. Place on ungreased cookie sheet. With fork, prick top of each to allow steam to escape. Brush tops with egg. Repeat with remaining ingredients.
Bake 9 to 14 mins. or until golden brown. Immediately remove from cookie sheet. Serve warm with dressing, if desired. Makes 24.
Recipe courtesy of The Butcher Shoppe.