Rustic Chicken Galette

Just why do I love Market of Choice?  The list is very long but one of the things I like most are the recipes they share in their weekly ad.  Love Month is a time to experiment with some fun new dishes and here is one that I enjoyed preparing and we enjoyed eating!  This makes 6 individual servings.
Pastry:  
3 1/4 C flour
1/2 C fine corn flour
3/4 T salt
3/4 T baking powder
3/4 C cold butter, cut into small cubes
1 1/2 T sugar
2 T sour cream
1 1/2 C ice water

Combine dry ingredients, cut into butter with mixer or by hand until crumbly.  Fold in sour cream and add water.  Dough will be similar to biscuit dough, wet but dry enough to handle and roll out.  Let rest 10 minutes.  On a generously floured surface, divide into six portions and roll out into thin 8-9" rounds, 1/8" thick.

Basic Filling:
1 1/2 T butter
1 ea. large Russet potato and yellow onion, diced
1 C mushrooms, sliced
1/2 T ea garlic, parsley, and fresh thyme, chopped
1 1/2 lb roasted chicken, shredded
3/4 C frozen peas
1/4 C ea white wine and chicken stock
1 C heavy cream
1/2 C Parmesan cheese, grated
1 t salt
1/2 t pepper
1 egg, beaten

Saute butter, potato and onion for 5 min.  Add mushrooms and garlic and cook 2 min more.  Add chicken, peas, parsley, thyme, wine,stock and cream.  Reduce by 1/3 (approx 3 min).  Add Parmesan and season to taste.  Divide filling among dough rounds and fold edges it toward the center, leaving middle exposed.  Brush dough with beaten egg.  Bake at 350 degrees for 25-30 min until golden brown.  Serve immediately.