Cook the Chicken: In a medium saucepan, simmer 1 ½ lbs of chicken in 1 ½ cups of chicken broth for about 15 minutes until cooked thoroughly. Once cooked, shred the chicken and reserve the broth for later.
Make the Filling: In a large skillet, melt 2 tbsp of butter over medium heat. Sauté 1 diced onion for about 4 minutes until translucent, then add 2 minced garlic cloves, 1 tsp salt, ½ tsp black pepper, and ½ tsp dried thyme. Stir in ¼ cup of all-purpose flour and let it cook for 2 minutes to create a roux. Gradually add in 2 cups of chicken broth and ½ cup of half-and-half, stirring continuously until thickened.
Combine & Simmer: Stir in the shredded chicken and let simmer for 10-15 minutes, stirring occasionally. If the mixture appears too thick, feel free to adjust it with additional broth. Fold in 2 cups of frozen mixed vegetables and heat through until warmed.
Assemble & Bake: Preheat your oven to 450°F (230°C). Pour the chicken filling into a baking dish, then spread 3 cups of warm mashed potatoes on top, creating texture using a fork for extra appeal.
Bake & Broil: Bake for 10 minutes until heated through. Then, switch to broil for 3-4 minutes until the topping is golden brown and slightly crispy. Allow the pie to sit for 5 minutes before garnishing with fresh chopped parsley and serving.
