In a large saucepan, melt butter. Stir in flour until smooth; gradually add broth and milk. Bring to a boil; cook and stir for 2 minutes or until thickened. Add the pork, vegetables, cheese, seasoned salt and pepper; heat through.
Transfer to a greased 11x7-in. baking dish. On a lightly floured surface, roll pastry into an 11x7-in. rectangle. Place over pork mixture. Brush with egg.
Bake, uncovered, at 425° for 18-22 minutes or until golden brown. Let stand for 5 minutes before cutting.