Another of John Ferguson's favorites.

Preheat oven to 350° convection.
Prepare two recipes of pastry dough. Finely chop onion, carrots and celery.
Sauté in olive oil in a large skillet over medium heat until slightly softened.
Add peas and season with thyme and marjoram.
Cook to warm peas.
Transfer to a large mixing bowl.
Cut chicken thighs and breast into bite-sized pieces and season with salt and pepper.
Wipe out your skillet and add some more olive oil.
Cook chicken in skillet until just done.
Add to vegetable mixture in mixing bowl.
Stir in the cream of mushroom soup to complete the pie filling.
Taste and season, if needed.

Pour pie filling into pie shell.
Roll out second pastry dough recipe to make top crust.
Beat egg and brush on the top edge of the pie shell.
Cover pie with top crust, pushing edges down on brushed edge of pie shell to "glue" it on.
Optionally, brush beaten egg on top pie crust.
Make sure to poke a hole or cut a slit in the top of the pie to allow steam to escape.
Cover edge of crust with a pie ring or aluminum foil to keep it from burning.
Bake pie at 350° (convection) until top crust is golden and pie filling is bubbling - 45 minutes to an hour.
Cool 10 to 15 minutes, slice and serve.