Turn thin tail of beef under and tie securely with string. The filet should be about 9 or 10 inches long after securing. Sprinkle salt, pepper, and garlic powder on top and place on a rack in a shallow pan. Roast in a preheated 425° oven 40 minutes. Remove from oven and cool. Cover and chill in refrigerator 4 hours or overnight.
Remove string. Open rolls and carefully unroll dough. Do not separate rolls. Arrange dough pieces to form a rectangle on a lightly-floured board. Pinch perforations together to make one piece of dough. With lightly floured rolling pin, roll dough to a 13x10-inch rectangle.
Place the chilled filet on dough, top side down. Bring edges of dough together down the center of the filet. Brush with lightly beaten egg white and pinch to close. Turn ends of dough under meat to form a smooth seam. Place filet, seam side down, in a shallow baking pan. Brush entire surface with egg white. Bake in a preheated 400° oven about 25 minutes, or until crust is browned. With two broad spatulas, lift filet to serving platter.
To serve, cut into thin slices.