This is how it all came together.
I diced up the turkey cutlets and seasoned them very well with salt pepper and a seasoning I get from my local butcher shop The Flying Butcher called crop dust. For those of you local reading this. Go get some and try it out for yourself, I don't think you will be disappointed.
In a skillet add a little olive oil and over medium high heat add the diced turkey. You want to brown all sides without over cooking the turkey too much. The browner you can get them the more depth of flavor you will get. Set aside the browned turkey. You will also be making the gravy in this pan so all the browned bits will help.
pick out the dish you are going to be baking the pie in and roughly shape the pastry sheet so you can place it on top. It does not have to be perfect, close is good enough. Then following the directions on the box of the pastry sheet bake the top in the oven for about 15-20 minutes. Set aside until you have the meat, veggies and gravy all together.
In a pot of salted water add the carrots and potatoes and cook till softened. remove from the heat and add the peas and celery. This will allow the peas to come to temp and just soften the celery enough while still remaining a little crunch to them.
In the pan you browned the turkey add a box of chicken stock scraping up all the browned bits. add a tablespoon of chicken base and taste for seasoning. Once you have it the way you like it. Make a slurry of flour and water. Yes I use water but you can use butter if you want to. Bring the stock up to a boil and slowly drizzle in the flour mixture whisking the entire time. Turn down the heat a little, you want it still bubbling and you want to stir it occasionally but you want it to become a thick gravy; while also cooking out the flour flavor.
Once the gravy is to your liking add the vegetables. mix all together and add to your baking dish. Top with scallions and cover with the pastry sheet and place in the oven for another 15 minutes or so. You want the crust cooked though and the veggie gravy mixture to heat till bubbly. Remove from the oven and let it cool slightly so you can enjoy it without burning your mouth.