Preheat oven to 350 degrees F and coat a baking sheet with nonstick cooking spray.
2.
In a medium saucepan, melt butter. Add onions and saute over medium heat for 3 minutes. Add beer, stir 3 more minutes.
3.
Pour into a large bowl. Add chicken, bacon mustard, salt and pepper. Combine thoroughly.
4.
Cut or tear the bread dough into 6 equal pieces. Roll into balls. Press and pull each ball into a flat circle, as thin as possible.
5.
Top circles with equal amount of chicken mixture, then with equal amounts of shredded cheese. Pull edges together and press to seal. Brush each ball with egg white.
6.
Place them on baking sheet and bake about 20 minutes, until golden brown.