I came cross this recipe in a magazine many years ago. My husband loves it and company is impressed by the presentation and the flavors! It has been our "go to" recipe for St. Patrick's Day every year since! Slainte!
At least 4 hours before serving, cook corned beef according to package directions. Cool to room temperature. (I have also cooked the meat the night before and then continued the recipe 1-1/2 hrs before serving.)
Combine sour cream, horseradish, mustard, parsley and pepper. Set aside.
On a lightly floured surface, roll out dough into 9x13" square. Cut a 3" strip from one side of the dough (making the dough 13/10"). Optional: Using a 2-1/2 x 3" shamrock shaped cookie cutter, cut out shamrocks from from the 3" strip.
Place corned beef at one end of the pastry. Spread it with 1 cup of sauce. Fold pastry edge up and over the meat. Brush dough edges with water, pinch together edged and tuck under. Brush shamrocks with water and arrange over top of pastry.
Place on cookie sheet sprayed with cooking oil spray. Brush with egg. Bake 20-25 minutes or until golden. cut into thick slices and serve with remaining sauce.