In another saucepan over medium heat, add 1/4 cup of butter.
Once melted, add onions and diced carrots. Mix well then cover and cook until carrots are soft.
One soft, add in turkey and frozen peas. Cover and cook for 2-3 more minutes peas are bright green.
Pour the creamy sauce over the filling mixture and combine well.
Pour the sauce and filling mixture into the prepared pie crust.
Then roll out the additional pie crust and cover the pie, crimping the edges, and adding several cuts in the center of the pie to release steam while cooking.
Using a basting brush, brush egg wash liberally over top crust.
Place in preheated 400°F oven, and loosely cover with a tented piece of aluminum foil.
Bake for 40 minutes covered. Then remove foil tent and let brown 10-15 more minutes until crust is browned.
Remove from oven and let rest for 15-20 minutes before eating - it can get very hot! Slice and serve. Top with fresh diced chives, if desired. Enjoy this Leftover Turkey Pot Pie!