Preheat oven to 375°F. On a lightly floured surface, roll dough into 12 by 19-inch rectangle. Cut into 8 rectangles, 4 by 5-1/2 inches each.
Combine beef, 1-1/2 cups cheese and onion, if desired, in large bowl; mix well. Divide beef mixture into eighths; press mixture to compact and place lengthwise in center of rectangles. Fold long sides of each rectangle over filling, pressing to seal. Place on ungreased shallow-rimmed baking sheet. Brush with egg white. Sprinkle with remaining 1/2 cup cheese. Cut small slit in top of each pocket to vent.
Bake in 375°F oven 13 to 16 minutes or until golden brown. Serve with sour cream. Garnish with chives, if desired.
Nutrition information per serving: 477 Calories; 216 Calories from fat; 24g Total Fat (10.8 g Saturated Fat; 0.3 g Trans Fat; 0.8 g Polyunsaturated Fat; 8 g Monounsaturated Fat;) 124 mg Cholesterol; 434 mg Sodium; 26 g Total Carbohydrate; 4.2 g Dietary Fiber; 38 g Protein; 4.6 mg Iron; 304.3 mg Potassium; 7.9 mg NE Niacin; 0.3 mg Vitamin B6; 2.5 mcg Vitamin B12; 9.9 mg Zinc; 32.1 mcg Selenium; 109.1 mg Choline.
This recipe is an excellent source of Protein, Iron, Niacin, Vitamin B12, Zinc, and Selenium; and a good source of Dietary Fiber, Vitamin B6, and Choline.