Step 1: Prepare Your Oven and Pan

Preheat your oven to 400°F (200°C). If using a pie crust for the bottom, line your 9-inch deep dish pie pan with one crust, pressing it gently into the corners and up the sides. Trim any excess dough hanging over the edges, leaving about 1/2 inch overhang. Set aside.

Step 2: Create the Roux Base

In a large 12-inch skillet over medium heat, melt the butter until it’s bubbling gently. Add the diced onion, carrots, and celery (this classic trio is called mirepoix). Cook for 6-8 minutes, stirring occasionally, until the vegetables soften and the onion becomes translucent. The vegetables should be tender but not browned. Add the minced garlic and cook for another 30 seconds until fragrant.

Step 3: Make the Creamy Sauce

Sprinkle the flour over the vegetable mixture, stirring constantly with a wooden spoon to coat all the vegetables. Cook for 2-3 minutes, stirring frequently—this cooks out the raw flour taste and creates your roux. The mixture will look dry and pasty, which is exactly what you want.

Gradually pour in the chicken broth, whisking continuously to prevent lumps from forming. Start with about 1/2 cup, whisk until smooth, then add the remaining broth. The mixture will begin to thicken as it comes to a gentle simmer. Continue whisking for 3-4 minutes until the sauce thickens noticeably and coats the back of a spoon.

Step 4: Add Cream and Seasonings

Reduce heat to medium-low and slowly stir in the heavy cream. Add the thyme, parsley, salt, pepper, garlic powder, and bay leaf if using. Let the sauce simmer gently for 3-4 minutes, stirring occasionally. It should have a thick, gravy-like consistency. If it’s too thick, add a splash more broth; if too thin, let it simmer a bit longer.

Step 5: Combine Chicken and Vegetables

Remove the bay leaf. Stir in the cooked chicken and frozen peas. Mix everything together until the chicken and peas are evenly distributed and completely coated in the creamy sauce. Taste and adjust seasonings—you may want more salt or pepper depending on how salty your broth was. The filling should taste well-seasoned at this point because it won’t get more seasoning once baked.

Step 6: Assemble the Pot Pie

Pour the hot chicken mixture into your prepared pie crust (or directly into a greased baking dish if not using a bottom crust). Spread it out evenly. Place the second pie crust over the top of the filling. Trim the edges to match, leaving about 1/2 inch overhang. Fold the top crust edge under the bottom crust edge and crimp decoratively with your fingers or a fork to seal. This prevents the filling from bubbling out during baking.

Step 7: Prepare for Baking

Cut 4-5 small slits in the top crust to allow steam to escape—this prevents a soggy crust and allows moisture to evaporate. In a small bowl, whisk together the egg and water to create an egg wash. Brush this mixture over the entire top crust using a pastry brush. This creates that gorgeous golden-brown, glossy finish.

Step 8: Bake to Golden Perfection

Place the pot pie on a baking sheet (to catch any drips) and bake in the preheated oven for 35-45 minutes. The crust should be deep golden brown and the filling should be bubbling up through the vents. If the crust edges brown too quickly, tent them with aluminum foil strips after 25 minutes.

Step 9: Rest and Serve

Remove from the oven and let the pot pie rest for 10-15 minutes before slicing. This resting time allows the filling to thicken further and makes serving much easier. The filling will be extremely hot, so this cooling period also prevents burns.