Sautee your veggies: Melt your butter over medium-low heat and add your onions once melted. Allow the onions to cook until soft and translucent, about 3-5 minutes. Add your celery and carrots and cook until carrots have softened, about 7-9 minutes.
Add flour and liquids: Sprinkle the flour over your veggies and stir to coat. Cook another minute. While whisking to avoid lumps, pour in your broth and milk or cream and simmer for one more minute.
Add chicken: Add your rotisserie chicken (or cooked chicken breast cubes) along with your frozen peas and chopped thyme. Cook one minute and add salt and pepper to taste.
Prep pie pan: Roll out your store-bought (or homemade) pie crust into the bottom of your pie pan.
Fill the pan: Transfer your pot pie mixture into the pie pan.
Add top crust: Add your second crust on top of your filling and crimp edges with the bottom pie crust. You can either cut slits into the top crust for vents or use a small cookie cutter to cut a few shapes. You can also brush an egg wash on top with an egg yolk mixed with a tablespoon of water for a shinier more golden crust.
Bake pot pie: Bake your pot pie at 425° for 30-35 minutes until heated through and golden brown. Check the pie 15-20 minutes in and if your crust is getting too dark, use a pie shield or piece of foil to keep your edges from getting too dark.
Let pie cool: Allow your pie to cool for 15 minutes to firm up a little before cutting into it to serve. Enjoy!
Notes
Tips for Making Chicken Pot Pie
Put a cookie sheet in your oven while it preheats and place your pie pan on that to give the bottom crust a little more cooking heat.
Use a pie shield to keep the edges of your pie from getting too brown (or you can use a piece of foil with a hole cut out of the middle like I did).
Instead of simple slits cut into the top for vents, try a small cookie cutter to cut out a few shapes for a pretty or fun design!