Preheat your oven to 350°F.
In a large skillet over medium heat, melt the butter.
Whisk in the flour and cook, whisking constantly, until the mixture begins to bubble.
Gradually whisk in the milk, followed by the heavy cream, stirring until the mixture comes to a gentle bubble and thickens.
Add the onion powder, garlic salt, celery seed, black pepper, poultry seasoning, and sugar. Stir to combine.
Turn off the heat and add the chicken, carrots, peas, and potatoes. Gently toss until everything is evenly coated.
Divide the mixture evenly between four 6-inch pie pans.
Unroll the puff pastry and lightly roll it out on a floured surface. Cut out circles slightly larger than the tops of the pie pans.
Place a puff pastry circle on top of each pot pie, pressing down lightly around the edges.
In a small bowl, whisk the egg with a splash of water to create an egg wash. Brush the egg wash over the puff pastry tops.
Place the pies on a baking sheet to catch any drips.
Bake for 20-30 minutes, or until the puff pastry is golden brown and the filling is bubbly.
Allow to cool slightly before serving. Enjoy!