Mix beef with waterchestnuts, onion, mayo, mustard, and pepper.
Separate dough into 10 biscuits, press or roll each into a four inch circle. Spoon 2 tablespoons meat mixture onto center of each circle. Bring dough up over meat mixture and pinch edges together to form buns.
Place seam side down on lightly greased cookie sheet. Brush with beaten egg and sprinkle with sesame seeds.
Bake at 375 for 12-16 minutes or until golden brown.