Broccoli Cheddar Chicken Pot Pie

2 unbaked pie crusts: These will form the bottom and top layers of the pot pie.
2 tablespoons butter: Used to sauté the onions and garlic, adding richness to the filling.
1/2 white onion, chopped: Adds a mild, sweet flavor to the pie.
2 cloves garlic, minced: Provides a pungent flavor that complements the creamy filling.
2 tablespoons all-purpose flour: Works as a thickener for the creamy sauce.
1 cup whole milk: The base for the creamy filling, adding moisture and richness.
4 oz cream cheese, softened: Adds creaminess and a slight tang to the filling.
1/4 teaspoon ground mustard: Provides depth and a hint of spice.
2 cups sharp cheddar cheese, grated and divided: Imparts a strong, tangy flavor; used both within the filling and as a topping.
3 cups cooked chicken, chopped or shredded: The main protein component, adding heartiness.
1 1/2 cups frozen broccoli florets: Adds color, texture, and nutrients.
Kosher salt and freshly ground black pepper: Enhances all the flavors in the pie.
1 egg: Used for an egg wash to give the pie a golden and crisp crust.

Preheat your oven to 350°F (175°C).
Grease a 9-inch pie dish with butter or nonstick spray.
Line the bottom of the dish with one of the pie crusts, gently pressing it to fit. Trim any excess crust from the edges.

In a large skillet, melt butter over medium-high heat.
Add chopped onions and sauté until they begin to soften (about 2 minutes).
Add minced garlic and continue cooking for another minute until fragrant.
Sprinkle in the flour and stir continuously for about one minute to cook off the raw flour taste.
Gradually pour in the milk while continuously stirring to prevent lumps. Follow with the softened cream cheese.
Keep stirring until the cream cheese is fully incorporated and the mixture thickens.
Season with ground mustard, salt, and black pepper.
Remove the skillet from heat. Stir in 1 1/2 cups of grated cheddar cheese until melted and smooth.
Fold in the cooked chicken and frozen broccoli florets until evenly distributed.

Transfer the chicken and broccoli filling into the pie crust.
Sprinkle the remaining 1/2 cup of cheddar cheese over the filling.
Cover with the second pie crust. Seal the edges by crimping with a fork or by pinching with fingers, ensuring the filling is enclosed.
Cut four small slits in the top crust to allow steam to escape during baking.

In a small bowl, whisk together one egg with 1 tablespoon of water. Brush this egg wash over the top crust to help achieve a golden color.
Place the pie in the oven and bake for 40-45 minutes, or until the crust is golden brown and the filling is bubbly.
Allow the pie to rest for about 10 minutes after baking. This resting period helps the filling set, making the pie easier to slice.

Cut into wedges and serve warm. Enjoy the creamy, savory flavors of your homemade Broccoli Cheddar Chicken Pot Pie!

This expanded version provides step-by-step instructions to ensure clarity and ease during preparation, enhancing your cooking experience!