Step 1: Preheat your oven to 400°F (200°C). Get all your ingredients ready by shredding the chicken, dicing the onion, and mincing the garlic. This prep work keeps everything organized and speeds up the process.

Step 2: In a large skillet, sauté the diced onion and minced garlic over medium heat until they turn translucent. Add the mixed vegetables and cook for a few minutes, then stir in the flour to form a roux. This step helps thicken the sauce and lock in flavors.

Step 3: Slowly whisk in the chicken broth and milk, stirring constantly to avoid lumps. Let the mixture thicken, then add the shredded chicken, salt, pepper, and thyme. Simmer for about 5 minutes to blend all the tastes together nicely.

Step 4: Roll out the thawed puff pastry on a floured surface. Transfer the chicken mixture into a greased pie dish and cover it with the pastry. Trim any excess and seal the edges for a neat finish.

Step 5: Make a few slits in the pastry to let steam escape, and brush it with the egg wash for a golden glow. Bake for 25-30 minutes until it’s puffed and brown. Let it cool a bit before serving warm with a side dish.