Preheat oven to 350°F. Lightly grease a 12 x 15-inch cookie sheet with non-stick cooking spray.
Unfold puff pastry sheet onto prepared cookie sheet.
Spread mustard over pastry sheet.
Place meats over sheet in layers, first pastrami, then turkey and corned beef.
Roll dough as for a jelly roll, place seam side down and brush with beaten egg.
Sprinkle with sesame seeds.
Bake, uncovered, at 350°F for 45 minutes to 1 hour, until slightly browned and flaking. Let stand 5 minutes before slicing and serving.
Recipe Courtesy of QUICK & KOSHER Recipes From The Bride Who Knew Nothing by Jamie Geller (Feldheim 2007) - BUY NOW
