In a large pot melt butter over medium heat. Slowly whisk in flour until you achieve a smooth golden roux.
Add onions and continue to stir until the room starts to smell amazing (about 3 minutes).
In a separate pot heat chicken stock with chicken bouillon cubes until dissolved.
Add celery and potatoes to roux. Stir well.
When bouillon are cubes dissolved into stock slowly add to the roux until it's creamy and smooth (stir in heavy whipping cream to make even smoother).
. Add frozen vegetables and cook a few more minutes. Add chicken. Let simmer stirring occasionally.
Preheat oven to 350°F.
Unroll dough and cut into circles to cover ramekins.
Pour mixture into ramekins.
Cover with dough, crimp ends, brush tops with butter or egg wash and bake for about minutes minutes or until golden brown.
Remove from oven and let cool for 10 minutes before serving.