In a large skillet, heat the butter over medium heat. Add the chopped onion and garlic and sauté until softened. Sprinkle the flour over it, stirring constantly for 1-2 minutes to cook the flour to make a roux. Gradually pour in the heavy cream and chicken broth while stirring continuously to create a creamy sauce. Cook for a few minutes until the sauce thickens. Add in the cheese, broccoli, potatoes, carrots, and chicken.
Simmer longer until the sauce thickens again slightly. Stir in the salt, pepper, and garlic powder. Spoon the broccoli cheddar mixture into 2-3 large ramekins.
Add puff pastry to the top of the ramekins, cutting off any excess. Brush the edges of the puff pastry with the beaten egg.
Bake the mini pot pies in the preheated oven for 20-25 minutes or until the pastry is golden brown and the filling is bubbly.
Allow the mini broccoli cheddar pot pies to cool for a few minutes before serving. Enjoy your delicious mini pot pies!
Notes
Storage: Store leftovers in a sealed container in the refrigerator for up to 3 days.