Follow these simple steps to create your delicious mini chicken pot pies:

1. Preheat the Oven: Preheat your oven to 425°F (220°C).
2. Prepare Filling: In a large skillet, sauté the chopped onion over medium heat until translucent, about 5 minutes.
3. Make the Sauce: Stir in the flour and cook for 1 minute, then gradually whisk in the chicken broth and milk. Cook until the mixture thickens, about 3-5 minutes.
4. Combine Ingredients: Add the diced chicken, mixed vegetables, garlic powder, onion powder, thyme, salt, and pepper. Stir until well combined and heated through.
5. Roll Out Crusts: Unroll the pie crusts on a lightly floured surface. Use a round cutter or a glass to cut out circles that will fit into your muffin tin.
6. Assemble Pies: Place the crust circles into a greased muffin tin, pressing them gently into the bottom and sides. Fill each crust with the chicken mixture, being careful not to overfill.
7. Top with Crust: Cut additional smaller circles from the remaining pie crust, and place them over the filling. Seal the edges by crimping with your fingers or a fork. Cut slits in the top crust to allow steam to escape.
8. Apply Egg Wash: Brush the tops of the pies with the beaten egg for a golden finish.
9. Bake: Bake in the preheated oven for 25-30 minutes or until the crust is golden brown.
10. Cool and Serve: Remove from the oven and let the mini pies cool for a few minutes before serving.