Preheat: preheat oven to 400℉.
Melt Butter: In large cast iron skillet (I use a 10.25) melt the butter over medium high heat
Sauté Veggies: Add onion and cook until softened and translucent. Add garlic and saute an additional 30 seconds until fragrant.
Thicken: Stir in flour and cook for 2-3 minutes.
Whisk in chicken broth.
Add the frozen vegetables, and cooked chicken.
Season: add salt, pepper, paprika, and poultry seasoning.
Cook: Bring this to a simmer. Remove from heat. Taste and adjust seasonings if needed.
Cut Puff Pastry: cut the pastry into desired shape. You can use a biscuit cutter to make small circles or you can cut the pastry with a knife into square shapes.
Top with Pastry: Lay the pastry over the top of the filling, be careful not to layer the pastry or it won't bake completely through and you will end up with a doughy texture.
Egg Wash: In a small bowl whisk together the egg wash by adding a splash of milk into the beaten egg.
Brush the top of the pastry with the egg wash.
Sprinkle the top of the pastry with salt, garlic powder and herbs.
Bake: Bake at 400℉ for 20-25 mins until golden. Puff pastry will be puffed up and golden on the top. Serve warm