In a large skillet, melt ¼ cup of butter over medium heat. Once the butter is bubbling, add the chopped onion, poultry seasonings, and fresh thyme. Sauté until the onion is translucent and soft, about 5 minutes.

Add the chopped carrots, celery, and minced garlic to the skillet. Stir well and sauté for an additional 8 to 10 minutes, until the carrots are tender and vibrant in color.

Sprinkle ½ cup of all-purpose flour into the skillet, stirring continuously until the flour is lightly golden, about 2 minutes. Gradually pour in 2 ¾ cups of low-sodium chicken stock while whisking to prevent any lumps.

Continue cooking until the mixture thickens into a creamy sauce, around 3-5 minutes.

Stir in 4 cups of shredded cooked chicken, ½ cup of heavy cream, and 1 tablespoon of chopped parsley into the thickened sauce. Mix until everything is evenly combined and heated through, about 2 minutes.

Turn off the heat and add 1 cup of frozen peas directly into the mixture, stirring gently. Allow the filling to cool completely in the skillet, which will take around 10-15 minutes.

Preheat your oven to 360ºF (180ºC). Roll out the puff pastry on a lightly floured surface and cut it into circles slightly larger than your pie bowls.

Distribute the cooled filling among the bowls, brush the edges with a beaten egg, and gently place the pastry circles on top, sealing the edges and cutting small slits for steam to escape.

Carefully place the assembled mini chicken pot pies in the preheated oven and bake for 30-40 minutes, or until the tops are golden brown and puffed.