In this easy chicken pot pie recipe, the flour combines with the butter and olive oil to create a simple, no muss, no fuss roux. Then broth and heavy cream are added to create the base of the creamy gravy. It thickens naturally as it's simmered on the stove and while the casserole is baking in the oven. It could not be easier to get a thick, creamy pot pie filling than with this recipe!