Add the onion and saute over medium-low heat for about 3 to 5 minutes.
Add half the salt once the onion has softened and continue to cook for another 5 minutes or until translucent. Do not brown the onion.
Add the flour and cook over low heat, stirring constantly, for 2 to 3 minutes.
Add water or the chicken stock and chicken broth flavor to the sauce. If you are using chicken stock, reduce the amount of salt by half.
Simmer over low heat for an additional 3 to 4 more minutes, stirring, until thick.
Add salt, pepper and heavy cream, cook for 2 to 4 minutes. Make any necessary adjustments to the sauce. If it is too runny, make a slurry: about 1 teaspoon flour with with a little water until it is the consistency of heavy cream. Pour into the sauce stirring vigorously. If too thick, add a little more water or chicken stock, little by little until the right consistency is achieved.
Add veggie mix and herbs. Mix well and cook until veggies are cooked through.
In the meantime, unroll the dough and using a circle cutter or a pizza cutter, cut the dough into circle or square pieces.
Set the cut pieces aside and roll the leftover dough and continue to cut into circles or squares.
Once the chicken pot pie has finished cooking, set aside to cool briefly.
Place one of the puff pastry pieces in front of you, scoop about 1 tablespoon of the mixture onto the pastry in the center. Do not overfill or you won’t be able to seal the edges and the pie will “explode” in the oven.
Optional, paint the edge on one half of the dough with a little bit of water. This helps to make the sealing easier.
Carefully fold the pastry over the chicken mixture to form a semi-circle or a triangle and press down the edges.
Use a fork to create a pattern on the edge. Put the finished pie onto baking tray lined with aluminum oil and sprayed with oil or parchment paper, and continue until all the pastry pieces are filled.
Beat the egg well then brush the top of each pie with the egg.
Bake until the pie is golden brown, about 10 to 13 minutes.
Remove from oven and allow to cool on a cooling rack.
Put the next batch into the oven and continue to cook until all the pies are done.
Once you have made the chicken pot pie mixture, how you serve it is absolutely up to you. For this recipe, I made mini hand pies. In the past, I have a regular large sized pie, about 9" and I have also made personal small pies about 4" wide. Play around with it. I also admit, just eating the chicken pot pie without the crust is just as good.