Prepare the Ingredients: Dice the chicken and potatoes into small, bite-sized pieces. Set aside the vegetables (peas, carrots, and corn).
Cook the Chicken: In a large skillet, melt 2 tablespoons of butter over medium heat. Add the diced chicken and cook for 6-8 minutes until browned and cooked through. Remove from the skillet and set aside.
Cook the Potatoes and Vegetables: In the same skillet, add the remaining 1 tablespoon of butter and melt over medium heat. Add the diced potatoes and cook for about 5-6 minutes, stirring occasionally. Then, add the frozen peas, carrots, and corn, and cook for an additional 3-4 minutes.
Make the Filling: Sprinkle the flour over the chicken and vegetable mixture. Stir to coat evenly. Gradually add the chicken broth and milk, stirring constantly until the mixture thickens (about 4-5 minutes). Season with garlic powder, thyme, salt, and pepper to taste.
Assemble the Pot Pies: Preheat your oven to 375°F (190°C). Roll out the pie dough and cut into circles using a biscuit cutter. Press the dough into a muffin tin to form the bottom crust. Spoon the filling into each muffin cup.
Add the Top Crust: Place another circle of pie dough over each filled muffin cup. Press the edges to seal and cut a small slit in the top for venting. Brush the tops with a beaten egg wash for a golden finish.
Bake: Place the muffin tin in the oven and bake for 25-30 minutes, or until the crust is golden brown and the filling is bubbly.